Chem: Ch. 2
n=2
8 is max # of electrons
Nuetron
0 charge or uncharged mass (g): 1.6750 x 10⁻²⁴ mass (amu): 1.0087 charge: 0 location in atom: nucleus
1 amu =
1.66054 x 10⁻²⁴ g
John Dalton
1766-1844 First person to coin to the word atom. Have not known about them since the beginning of history. Sort of a recent development in human history that started talking about atoms First scientific description of atoms, based on careful measurements and experiments, proposed in 1800s by this English scientist Dalton's Atomic Theory
n=3
18 is max # of electrons
n=1
2 is max # of electrons
more than
300 naturally occurring radioisotopes (unstable nuclei - what happens: usually atoms near the bottom of the periodic table where they have lots of protons and neutrons in the nucleus and the great big atoms have so many of those that they are not stable. What happens is the nucleus breaks apart into smaller pieces in a number of different ways) have been identified
n=4
32 is max # of electrons
1 g =
6.022 x 10²³ amu (Avogadro's which defines a mole. Definition also used to define the AMUs. AMU is a unit of mass, but just very small unit) AMU scale helps us write the mass a lot easier than with the g scale
ground state (Bohr model of the atom)
An atom in its ground state (most stable electron arrangement) when its electrons are in energy levels as near as possible to the nucleus.
Oxygen
Atomic Symbol: O Origin of Name: From the Greek oxy and genes (acid-forming) % of body weight: 64.6% Biochemical Significance: An element present in many organic and biochemical compounds.
Phosphorus
Atomic Symbol: P Origin of Name: From the Greek phosphoros (bright light) % of body weight: 1.5% Biochemical Significance: Important to the structure of bones and teeth and is present in nucleic acids. RDA (mg/day): 700 UL (mg/day): 4000 Problems associated with overconsumption: Skeletal problems Problems associated with under consumption: Rickets
Lead
Atomic Symbol: Pb Origin of Name: The Anglo-Saxon name for the element. Symbol from the Latin name plumbum
Plutonium
Atomic Symbol: Pu Origin of Name: Named after Pluto
Sulfur
Atomic Symbol: S Origin of Name: From the name for sulfur in Sanskrit (sulvere) and Latin (sulfrium) % of body weight: 0.3% Biochemical Significance: Present in some amino acids, proteins, and vitamins.
Tin
Atomic Symbol: Sn Origin of Name: Anglo-Saxon name for element. Symbol from Latin stannum
Uranium
Atomic Symbol: U Origin of Name: Named after Uranus
excited state (Bohr model of the atom)
If an atom absorbs energy, its electron is pushed to an orbit farther from the nucleus, resulting in the atom to be in this state.
atomic weight versus atomic mass
Atomic weight is different from atomic mass. Mass numbers are always whole numbers (no decimals because just counting). Atomic mass/weight will have decimal places in it and it is the weighted average of all the isotopes factoring in the natural abundance of the isotopes
Dalton's Atomic Theory (John Dalton)
Atom is the basic unit from which all matter is constructed. (TRUE) All matter (air, table, water, etc) is composed of atoms. Matter is everything except a vacuum. Matter is all made up of atoms and those atoms are all made up of many different ways. Atoms themselves can be broken into protons, neutrons, and electrons. Dalton did not know about protons, neutrons, and electrons. Now we know the atom itself is consisting of even smaller particles. Dalton's view of the atom: the atom is an indivisible unit of matter. Cannot break it apart any further, which is true because you cannot break it apart any further and it still has its same chemical and physical properties. However, our modern view now has atoms have protons, neutrons, and electrons in it. When we break an atom into those smaller pieces, it no longer has the same chemical and physical properties that it has before. It being indivisible is true if not going to alter the original chemical and physical properties. Further studies into the nature of the atom gave results that led to revisions of this theory. In the mid-1800s, discovered "rays" being emitted and in 1887 rays named electrons and were understood to be subatomic particles (particles smaller than the atom) from which atoms are made from. Other two subatomic particles = protons (1919) and neutrons (1932)
Silver
Atomic Symbol: Ag Origin of Name: From the Anglo-Saxon name for the element, siolfur. Symbol from Latin argentum
Gold
Atomic Symbol: Au Origin of Name: From the Sanskrit jval (to shine). Chemical symbol Au is from the latin aurum (glow of the sunshine)
Carbon
Atomic Symbol: C Origin of Name: From the Latin carbo (charcoal) % of body weight: 18.0% Biochemical Significance: The main element present in organic and biochemical compounds.
Calcium
Atomic Symbol: Ca Origin of Name: From the Latin calx (limestone) % of body weight: 1.9% Biochemical Significance: Important to the structure of bones and teeth and plays a role in membrane function in muscle contraction. AI (mg/day): 1300 UL (mg/day): 2500 Problems associated with overconsumption: Kidney stones Problems associated with under consumption: Osteoporosis (brittle bones) and retarded growth (in children) micro nutrients - used to form strong and good bones
Chlorine
Atomic Symbol: Cl Origin of Name: From the Greek chloros (greenish yellow) % of body weight: 0.2% Biochemical Significance: Helps to maintain water balance.
Curium
Atomic Symbol: Cm Origin of Name: Named in honor of Marie and Pierre Curie
Copper
Atomic Symbol: Cu Origin of Name: From the Latin cuprum (From the island of Cyprus) Is a trace element Biochemical Significance: Required for hemoglobin formation (see Iron).
Iron
Atomic Symbol: Fe Origin of Name: From iren, Anglo-Saxon for iron. Symbol is from the Latin name, ferrum (iron) Is a trace element Biochemical Significance: One component of hemoglobin, and oxygen-transporting component present in red blood cells. Do not need much. Needs 18 mg/day. Need because it has the component of hemoglobin (protein in RBC and main func: allow oxygen transport through our tissues). Breathing oxygen is not that soluble in water (which is what our blood mostly contains). If we were to allow oxygen to saturate our blood, it would not have oxygen carrying capability to supply our tissues and metabolic processes. Body has hemoglobin that contains iron in it and it is a great protein for transporting oxygen. Anemia: iron deficiency can occur if you do not get enough iron in the diet. If you have this, will feel very tired and not feel like doing anything. Body is not able to carry out all of the metabolic processes well because the body is oxygen deprived and without it is not able to act efficiently which is why you get tired feeling because tissues run out of oxygen and just feel very tired and run down. Will have to take iron pills, which will give you a supplement of the iron not getting in the diet. Get the hemoglobin up to its normal state with all the iron needed in it to help transport oxygen. RDA (mg/day): 18 UL (mg/day): 45 Problems associated with overconsumption: Liver, heart, and pancreas damage Problems associated with under consumption: Anemia be careful with it, but many do not have trouble with getting to much
Hydrogen
Atomic Symbol: H Origin of Name: From the Greek hydro and genes (water-forming) % of body weight: 10.0% Biochemical Significance: An element present in organic and biochemical compounds.
Helium
Atomic Symbol: He Origin of Name: From the Greek helios (sun)
Mercury
Atomic Symbol: Hg Origin of Name: Named after the planet. Symbol from Latin name hydrargyrum (quicksilver)
Iodine
Atomic Symbol: I Origin of Name: From the Greek iodes (violet) Is a trace element Biochemical Significance: Required for the production of thyroid hormones. RDA (mg/day): 0.15 UL (mg/day): 1.1 Problems associated with overconsumption: Decreased synthesis of thyroid hormones Problems associated with under consumption: Impaired learning
Potassium
Atomic Symbol: K Origin of Name: From English potash. Symbol from Latin kalium % of body weight: 1.2% Biochemical Significance: Important for transmission of nerve signals and muscle contraction and involvement in maintaining water balance.
Magnesium
Atomic Symbol: Mg Origin of Name: From Magnesia, region of Thessaly Greece % of body weight: 0.1% Biochemical Significance: Present in compounds that play a role in metabolism (chemical changes that take place in the body).
Nitrogen
Atomic Symbol: N Origin of Name: From the Greek nitron and genes (Nitre-forming). Nitre = older name for potassium nitrate/saltpeter % of body weight: 3.1% Biochemical Significance: Important to the structure of nucleic acids (DNA and RNA) and proteins.
Sodium
Atomic Symbol: Na Origin of Name: From the English soda and Arabic sûda (soda). Symbol from natron, alchemists' name for soda % of body weight: 0.2% Biochemical Significance: Important for transmission of nerve signals in muscle contraction and involved in maintaining water balance. RDA (mg/day): 1500 UL (mg/day): 2300 Problems associated with overconsumption: Hypertension, increased risk of cardiovascular disease, heart attacks, and stroke Problems associated with under consumption: Nausea, cramping, convulsions have to be really careful with it, many natural foods that were not processed have this. Processed has more sodium than we need. Most exceed RDAs and UL
Neon
Atomic Symbol: Ne Origin of Name: From the Greek neos (new)
Mole
Atoms are so/extremely small that the only time they are dealt with one by one is in experiments that rely on very specialized scientific instruments. Sometimes there are a lot of atoms involved. As a result, the numbers of atoms are best represented using a unit called this (unit used for counting atoms and molecules. Chemists count things in terms of mole. Large number of things = mole). Mole is defined by the number of atoms in the Carbon-12 isotope of 12 grams Very small element contains a huge number of atoms. Moles help deal with the large amount of atoms. 1 mole = 6.02 x 10²³ (Avogadro's number) which is = number of atoms in 12 grams of pure carbon-12 Mole is incredibly large number of items, atoms are so small that one mole of them in a solid/liquid state does not occupy a lot of space Mole = standard unit used to indicate the number of atoms present in a sample. Useful to be able to convert between moles and number of atoms (factor label method) Mole is not good for indicating mass, unless you know something about the mass of individual items. If an element has greater mass than another one, you know that one mole of the greater element is more than one the other element molar mass
isotopes
Atoms of a particular element will always have the same number of protons, but the number of neutrons will differ. Isotopes: atoms of an element that have different # of neutrons/elements that have the same number of protons and diff number of neutrons. 2 atoms that have the same atomic number but diff mass numbers. Atoms that are the same element with a different number of neutrons Isotopes can give elements different names. All elements have more than one isotope and the isotopes of an element usually not present in nature in equal amounts. Every atom or element in the periodic table has at least 2 isotopes meaning it can have different numbers of neutrons A lot of people immediately think of radioactive with this Atomic symbol can indicate a particular isotope Most elements do not have special names for isotopes by H does, which is rare. Element-mass number demonstrates different isotopes (H-3) Radioactive isotope: elements that appear in the bottom of the periodic table and need to stay away from them because they have radioactivity associated with them. Not all isotopes are radioactive. H-1, H-2 are not radioactive, but H-3 is. Some isotopes are radioactive and some are not. Just depends on a particular combo of neutrons and protons Difference between isotopes is number of neutrons Iron has several isotopes See below for example: red is proton. First one is called Hydrogen-1 or H-1, which is the normal one and more common hydrogen isotope in the universe. Hydrogen-2 or H-2 (has one neutron and one proton): aka deuterium. Hydrogen-3 or H-3 (has two neutrons and one proton): tritium.
valence shell
Atoms of elements in the same group have identical number of electrons in their valence shell (highest numbered, outermost occupied energy level; outermost shell occupied)
In 1926
Austrian physicist Erwin Schrodinger found that electrons can behave as energy waves, rather than particles. Used wave-like properties of electrons to devise a mathematical equation that described electron energy levels in a new way. Called quantum mechanics, viewed as an atom at having a series of energy levels. Assigned electrons to various atomic orbitals (3-D regions of space where there is a high probability of finding an electron). Orbitals - electron clouds. EX: s and p orbitals. Quantum mechanics is useful because it lets us calculate the max # of electrons that any particular energy level can hold. Max number of elections per energy level = 2n^2. N = # energy level. n=1-4 is energy states Described atoms in a new way based on a mathematical model (quantum mechanics). Treated the electron as a wave. More complicated mathematical model is what we go by today because it works for all atoms, while Bohr's model only did for Hydrogen In this quantum mechanical medal, the electrons are assigned to various atomic orbitals. One of the things we are interested in is to predict where those electrons are going to be located around the nucleus and his work allows us to do this. His models could give us probability of where the electron might lie With this model (matches closely with Bohr), electrons are grouped around the nucleus in shells and each shell has a different energy level. Shell closest to the nucleus = shell 1 or n=1. Outer shells are further from the nucleus, larger, tend to hold more electrons because they have more space, and have higher energy. Higher energy levels means further from the nucleus and more volume available for the electrons to exist probability shapes
The mass of C-12 is
C-12 is exact and everything in the periodic table is based off of it. In 1961 began using Carbon standard for atomic masses
Atoms
Consist of protons, electrons, and neurons
Bohr model of the atom
Danish physicist Niels Bohr proposed the colors of light in hydrogen's emission spectrum directly related to the movement of electrons. Neils Bohr studied this and wondered why we did not get all different colors from the Hydrogen lamp? Why are we only getting specific colors? Came up with some series and decided that the electrons must be arranged an atom's nucleus in layers. Nucleus is in the middle filled with protons and neutrons. The first shell/level is where some electrons can reside. Second level, higher in energy, and where other electrons may exist because they are complicated elements. Each level represents an energy level. The higher the level the higher energy, and the lower the level, the lower energy. Bohr predicted that electrons must be jumping from one level to another. Levels are concentric layers. Many levels for one element Electrons tend to want to occupy the lower energy levels/lowest energy states first. Violet light has more energy (fall at greater distance) than red light and the reason we know that is based on how far the electron fell When an electric current is passed through a tube containing hydrogen gas, the light emitted by the hydrogen atoms can be separated by a prism and viewed as an emission spectrum (a series of colored lines). In the last century the Danish physicist Niels Bohr proposed that the colors of light in the emission spectrum of hydrogen are directly related to the movement of a hydrogen atom's electrons between different energy levels. Early attempt to describe electron arrangements. Electrons circle the nucleus in specific orbits, with each orbit corresponding to a diff energy level. When an electron jumps to an orbit nearer the nucleus, energy is released Violet/purple light has more energy than red light. Know this because with the red light it only falls one level, but with different colors it drops more or at a greater existence showing more emission and energy released Bohr believed that the emission spectrum of hydrogen is produced when H atoms move from various excited states back to stable states, releasing energy. Energy given on = electromagnetic radiation (type of energy that travels in waves). The changes in energy result in different light colors. Red - lowest energy. Violet - highest energy Very good at explaining the emission spectrum of H, but not other elements. Gives us a way to look at the atomic spectrum. Bohr's model in explaining the emission spectrum, but it didn't explain to well what happens for other atoms/more complicated atoms with more protons and electrons in it Hydrogen emission spectrum absorption emission law of conservation of energy ground state excited state
What are atoms called if they have the same mass numbers, but different atomic numbers?
Different elements
Nutrition Facts Label
Helps consumers understand the nutritional content of foods Standardized format for how the government wants all manufacturing companies to put the facts on that What tells you: if concerned about weight, you will look at Calories (no recommended amount of Calories [food calories; 1 kcal/1000 cal = 1 Cal], government says we need 2000 Calories/day to maintain our weight). Have to be careful of serving size and pay attention to it. Pay attention to serving size and serving per container. Companies will trick you that there are only a certain amount of Calories, but if you look at serving size, you ate more than recommended and now at a high level of Calories. Food manufacturers try to trick people like this that will say low Calorie, but low serving size also. Sodium, Cholesterol, etc. has mg and percentage. Percentage does not mean the food is that much sodium. Instead it is that percent of your daily value. Some nutrients given in percent but no amount given because not looked at often *Percent daily value = amount of nutrient in 1 serving/daily value x 100 [exact] (WATCH SIG FIGS)* Daily value = amount that the USDA (US Department of Ag - agency whose role is to give us the amount we should be eating to stay healthy) says is ideal for daily consumption. Number the USDA says is ideal for us to have. Look up in a table from government First thing note is service size and number of Calories per serving, near top. Next section: lists the amount of nutrients present/serving and % of daily recommended daily amount. Some nutrients only have percent of daily value because it is independent of calorie intake. Required on most packaged food. Helps consumers make informed decisions % DV = part (food label)/whole (RDA) x 100%
periods (periodic table of the elements)
Horizontal rows As you move down the rows left to right, see periodicity occur. Some elements have periodic chemical and physical properties that repeat themselves. Atomic size decreases as it moves from left to right. Left side tend to be bigger Furthest to the left are more metallic and furthest to the right are most nonmetallic. Metallic character decreases as go to the right Elements in the same horizontal row belong to the same period. Number 1-7 beginning with the first row "Period" relates to the periodic/regular changes that take place in the properties of elements as you move them in order of atomic number. The way the periodic table is set up dates back to late 1860s and work done by Russian Chemist Dmirtri Medeleev. Arranged known elements in a row in terms of increasing atomic weight and noted that the properties of the elements change from left to right. Similar properties for each period. Another periodic change related to metals, semimetals, and nonmetals. Atomic size is another property that shows periodic behavior. Decreases as move left to right and increases as moving down in a group Atomic size = atomic radius, which is the length/distance from the nucleus to the outermost electron. Atoms get smaller as they move to the right and increase as they go down. Smallest is to the right and top. Biggest elements lower left. Smaller as you go the right and bigger as you go to the bottom
electron dot structures
In early 1900s, American chemist Gilbert N. Lewis develop this to show the # of valence electrons that an atom carries. Valence electrons show/represented as dots. Dot = valence electrons. Atomic symbols represent the nucleus and inner/core electrons. Only show the outermost electrons/valence electrons. These help with bonding Only show the outermost/valence electrons Transition metals not used for this because they are unpredictable. When filling these out, imagine the atom as having four sides to it. Each side can have 2 electrons on it. When filling this out, put dots on opposite sides, not on the same side because you want to represent they have negative charges and since they are like charges, they repel each other. To show this, only draw the electrons on opposite sides where you put both dots on one side. Order of filling: put one electron on each side first to keep them separated as much as possible and then pair them up. Electrons do not like to be close together but do not have a choice with this so you have to fill it in. 4 sides and each side has a max of 2 electrons. Fill up sides with one electron before go in and fill it up again by pairing them up One exception is Helium. Only 2 electrons and draw it with the two dots on the one side to show that it only has two and does not hold 8 electrons in it. Others you have the dots separated out as much as possible Electrons are negative and repel each other Representation of the atom that specifically shows the valence electrons When filling out these, imagine the atom has four sides of it, and each side is only allowed to have 2 valence electrons. Do not put both dots on both sides because they are not going to want to be close together because they are the same charge. Do not put them together. When have 8 make sure they are directly across from each other to show how they are not the same, but then pair them up. When drawing pair them with others that match up on the opposite side, so we can show the same charges repel Helium is the exception. Put the two dots on the same side. Whereas you keep them spaced apart Electrons repel each other
periodic table of the elements
Is a complete list of the elements, arranged in order from smallest to largest atomic number. Atomic symbol, atomic number, and atomic weight (the avg mass of the atoms of an element, as it is found in nature/ avg mass of the atoms in a naturally occurring sample of the element) of each element are included in the table. In ours, it has a box which has the atomic symbol/name, atomic number (no units because just counting) on top, and atomic mass/weight (how much 1 atom weighs on average and no units because it can think about the mass of an individual atom in AMUs. Mass of a single atom in AMUs) put below the symbol. Or can think on the macroscale and look at moles Has not always been the way it is now. When it was first developed in 1869 by Russian Chemist Dmitri Mendeleev. Gets the credit for designing the periodic table, even though there are many others who worked on it. First one to publish his results in a Russian journal. Different than the one today. He put his in order of increasing atomic mass because back then they did not know about protons, neutrons, and electrons were part of the atom. Original periodic table was 90 degrees switched as he had rows as columns and vice versa. So confident in what he was doing in classifying elements based on their chemical and physical properties that he left holes in his periodic table that had not yet been discovered. Predicted some of the physical properties that had not been discovered and was accurate. Spent a lot of time categorizing and grouping the elements based on physical and chemical properties, which is the basis for our table. Some elements have the atomic weight in brackets because they are found as unstable isotopes and reported atomic weight is the mass number of the isotope that stays in existence for the longest Average atomic mass = given in periodic table. Use average because you do not always want to figure out how many of the atoms are from different isotopes. If we just do an average atomic mass, by the abundance and mass of the isotopes, we can get an average. metals, nonmetals, and semimetals groups periods
cobalt
Is a trace element Biochemical Significance: Required for the production of red blood cells.
What are atoms called if they have the same atomic number but different mass number?
Isotopes
molar mass (mole)
Mass (g) of one mole of its atoms/molecules/whatever counting, is numerically = to the atomic weight of the element in amu. Units are always g/mole Mass of the atoms from periodic table Numerically = to the atomic weight of the element (Mass in grams of one mole of atoms of the element) is = to its atomic weight (mass of a single atom in AMUs). This same number works for a mole of atoms. Atomic weight is also the mass of one mole of the atoms in grams. No units in periodic table because we can think about individual atoms in terms of AMUs and mole of those atoms in grams. Average atomic weight and mole of atom are = to each other EX: 6.94 amu = atomic weight of lithium so the molar mass = 6.94 g/mol of Li
Concept map for mass, moles, and molecules/atoms:
Mass to moles: the conversion factor is the molar mass (how much does a particular mole of a substance weigh in grams). Dividing by the molar mass (from periodic table, aka atomic mass) Moles to mass: Multiply by the molar mass Moles to atoms: multiply by 6.022 x 10^23 (Avogadro's number; very large number) Atoms to moles: divide by 6.022 x 10^23 Almost always have to go through moles if counting something. No direct relationship between atoms and mass; have to go through moles first. Let the units guide you WRITE OUT UNITS AND ELEMENT (either with the symbol or name) Use all digits in molar masses provided in the periodic table so you do not incur rounding error For counting atoms always have to go through moles Always ask yourself the sort of ballpark answer that you are expecting
nuclear change/reaction
Matter can undergo physical changes, chemical changes, and change to atomic nuclei. This nuclear change/reaction (weird stuff is going on) differs from the other two because atoms are altered during the process. Changes in the nucleus. Several medical treatments that use radioactive isotopes for these things (radiation therapy for cancer - done by giving a patient a dose of nuclear radiation that comes from chemical/nuclear reactions - occur in the nucleus itself. In many of these cases we have an element changing its identity from one element to another because if the nucleus gets rearranged (loses or gains protons), changes identity of the element - which is based on the number of protons only). If changing something in the nucleus that is causing that number of protons to be different, changes the identity of the element. Something new is created - when an atom's nucleus changes so does the identity of the atom.
Manganese
Mn Is a trace element Biochemical Significance: Required for normal growth and plays a role in metabolism. AI (mg/day): 2.3 UL (mg/day): 11 Problems associated with overconsumption: Heart rhythm problems Problems associated with under consumption: Unknown
energy levels
N = # energy level. n=1-4 is energy states. Each energy level has a max number of electrons it can hold. Electron shells further from the nucleus can hold more electrons than level closer to the nucleus (n=1 is the closest and not much volume). As we move further out, there is more space for more electrons. Can have fewer electrons than max in the shell. Higher energy level = farther away from nucleus and more volume available for the electrons
metals, nonmetals, and semimetals (periodic table of the elements)
One way the elements can be grouped. Elements can be grouped in these three different categories Bold zigzag line separates the metals and nonmetals Metals are to the left of line, except hydrogen which is a non-metal. Semimetals border the zigzag line. Vast majority are metals. Majority of the table Metals are good conductors of electricity and heat. As solids, they are lustrous (shine), malleable (pound w/o breaking; if you hammer it out into thin foil, you can shape it. Not brittle, will just deform. Can shape it or beat it out to a thin foil), and ductile (drawn into wires; can take to sides and pull on them and it will draw out into a thin wire; kind of related to malleability). Solids at room temperature. Nonmetals do not behave like metals. Dull. Poor conductors of electricity and heat, and in the solid state, are non lustrous and brittle. Right side of zigzag line. Not as many. Opposite of metals. Not usually solids at room temperature (like sulfur is solid at room temperature). Not malleable, will just shatter because they tend to be brittle and not ductile. Hydrogen is on the far left side, but it is a nonmetal even though it is on the metal side Semimetals/metalloids have physical properties that are intermediate between metals and nonmetals. Along the staircase line. EX: Silicon and germanium (semiconductor - use for computer chips). Property of having conductivity between metal and nonmetal works well for electrical circuits. Some of these elements use all the time. In between and have characteristics of both. Decent at conductivity. Divides metals from semimetals
emission (Bohr model of the atom)
Opposite process: Have an electron in a higher energy level, may have been energized by an absorption process (absorbed some of the energy of the high voltage source and jumped to a higher energy level). Electrons naturally want to be in a lower energy level, so it is going to drop down to a lower level (first, second, etc). For the electron to drop, energy has to be released. Energy is released as light, which is what is creating the colors in the light band. When they drop, there is going to be energy released which causes light. Depending on how far it drops, determines how much energy is released resulting in different colors. Low energy light = red side of the visible light scale/range (electron does not have to drop as far). High energy light = violet side of the visible light scale/range (electron drops further). Process (energy comes out and electrons respond by moving to a lower energy level/shell) is called emission. ONE THAT PRODUCES LIGHT occurs simultaneously with absorption
To help nutritionists and medical professionals provide good dietary advice, 1941 the National Academy of Sciences (NAS) created
Recommended Dietary Allowances (RDAs): are daily intake of nutrients that are sufficient to meet the needs of 97-98% of healthy people. Number from government, amount recommended in one days time. Originally was designed to prevent diseases caused by nutritional deficiencies As understanding progressed, created in 1990s Dietary Reference Intakes (DRIs): helps health professionals make better nutritional recommendations. Include values RDAs just mentioned, Adequate Intake (AI) and Tolerable Upper Intake Level (UL). AI = used when RDA unavailable, daily intake of a nutrient believed to be sufficient to meet the needs of people; unreliable and percent of people this covers is unknown. UL = for some elements, do not want too much, there is this and you can look them up in tables Some RDA and AI values differ with age and/or gender.
Trace elements
Required for the body to function properly Elements that the body needs small quantities or amounts of if it is to function properly, but they are essential for proper bodily functions. Very small amounts of the particular elements are needed Make up less than 0.1% of total body weight, and for adults, required in less than 100 mg daily. Very tiny amounts of these things. May not be needed to build muscle or bone, so we do not need much, we need some to be able to have other systems function properly. Elements that the body needs in small amounts [called micros or micronutrient] Multivitamins help with this. Vitamins have minerals are some of the elements that look at. Pay attention to nutrition facts label to see what getting
Selenium
Se Is a trace element Biochemical Significance: In conjunction with Vitamin A, it acts as an antioxidant (prevents the breakdown of certain compounds). RDA (mg/day): 0.555 UL (mg/day): 40 Problems associated with overconsumption: Nerve damage Problems associated with under consumption: Cell damage
Nuclear change involves change to atomic nuclei:
Something new (element, electron, particle) is usually created The identity of the atom changes
probability shapes/orbital (quantum mechanics)
These diagrams are probability shapes/orbitals. Probability shape means: nucleus is in the center/origin of the axis system (3-D representations below) and this shape that looks like a sphere where on the surface or inside of it there is X% probability of finding an electron. Outside of it, there is a low probability of finding an electron. Weird thing about this is that it predicts weird shapes because there are some atoms where the electron's probability is higher in those areas than in between. Gives us an idea of where the electrons will be located Nucleus found at the origin. In the surface of shape or within shape, high probability of finding the electrons. Gives us an idea of where those electrons are going to be located
Allotropes
Two different forms of the same or particular element. Made up of the same thing, but connect in different ways. Carbon has multiple (diamond and pencil lead). Phosphorus as well Different arrangements of same atom. Mainly one atom. Not combo of atoms. Just way structured
atomic notation
Used to specify the number of protons and neutrons. If you have trouble remembering, the big number should always go on top. Atomic number does not have to be written because it is always going to have the same number of protons. So not always needed, could just get rid of 7, but mass number is required because it does vary. Mass number/bigger number always on top. Neutrons = mass number - atomic number. Do not always need atomic number because symbol and atomic number have the same info but need mass number Need to consider the symbol used based on periodic table based on atomic number To find number of neutrons when just given this take mass number - atomic number because we do not have a particular number just for the neutrons Big number goes on top. Atomic number = optional
groups (periodic table of the elements)
Vertical columns Atoms get larger as you move down a group and become more metallic as you move down Some groups have special names. Four below are the most common. Special names because many compounds are made from these elements in the groups Elements in the same vertical column belong to the same group. Alkali metals: group 1A Alkaline earth metals: group 2A Halogens: group 7A (really special because are pretty reactive and looking to fill their valence shells) Inert/noble gases: group 8A (Noble gases tend to be very stable and remain as pure elements. Do not find them in compounds.) Group 3A could also be called 13 if asked Periodic table can be divided into larger groupings of elements. Group 1A-8A = representative elements Group 1B-8B = transition metals Elements with atomic numbers 57-71 are lanthanide elements Elements with atomic numbers 89-103 are actinide elements Last two fit into the blank boxes but way arranged would be too long if out in the table so thrown on the bottom to make it more condensed
mass number
Ways to describe atoms Tells us about the isotope of the atom Total number of protons and neutrons in the nucleus of the an atom # protons + # neutrons in the nucleus Not the mass of the atom. Put more emphasis on number than mass. Atomic mass is also different than this ALWAYS WHOLE NUMBERS. Which is how it differs from atomic mass because atomic mass has decimals because we are counting things here Always goes on top Always greater than atomic number Atom's mass number is not the same as its mass. Mass number is simply a count of the protons and neutrons in an atom. Differ because protons, neutrons, and electrons do not have masses that are whole numbers. Also, not the same number because of the "mass defect". Atom is more stable than the collection of free subatomic particles from which it formed, so when an atom is created, a small amount of energy is released. Einstein showed that mass and energy are related. Energy is released when an atom is created comes from the loss of a small amount of mass. Missing mass = mass defect. Only element where the mass number and mass are identical is carbon (12 = mass number and 12 amu) because amu defined based off of this atom
atomic number
Ways to describe atoms The number of protons that an atom has in its nucleus. The number of protons or this determines the identity of that element (does not depend on neutrons or electrons) Is not required but goes on bottom Always less than mass number
absorption (Bohr model of the atom)
When applying a high electrical voltage to hydrogen, have an electron that might reside in n=1 and it is going to be energized by that energy with the high voltage source (5000 V; outlet = 110 V). The electron will jump to a higher energy level such as n=2 to n=3 if there is enough energy to do the jumps. We are putting energy in supplied by the voltage source. When energy is going in, the electrons tend to jump from a low to high energy state. Electron responds to energy going in by moving to a higher energy level/shell. Think of layers as shells that completely surround the nucleus. Process called absorption. Energy is being absorbed and electrons respond by moving to a higher energy level. occurs simultaneously with emission
Zinc
Zn Is a trace element Biochemical Significance: Required for normal growth, helps with wound healing, and required for smell and taste. RDA (mg/day): 11 UL (mg/day): 40 Problems associated with overconsumption: Nausea, vomiting, and dizziness Problems associated with under consumption: Loss of smell and taste, depressed immune sys
In modern atomic theory, the word element has
a different meaning than that of Greek philosophers. An element = substance that contains only one type of atom. Simplest substances. Might be aggregates of that atom to form an element, but only contain one type of atom. One atom and it takes on different forms for each thing it creates (diamond versus pencil lead)
as you go left to right,
atomic radii decreases because as you get more electrons as you get more protons pulling them in tighter. As you go bottom to top it decreases because less protons have less electrons so have less in and outside of the nucleus so just smaller atoms. F is one of the smaller ones
Ancient Greek philosophers
believed that matter was thought to be made from tiny, indestructible building blocks called atoms (atomos = Greek for indivisible)
elements at the bottom of the table have a
bigger atomic weight than something at the top because the location of the outer electron changes, not size of nucleus. Electrons are arranged in layers and the farther down the table the more electron layers present resulting in much bigger atoms
If we know an atom's atomic number and mass number, we
can determine the number of protons and neutrons. A neutral/uncharged atom has same # of protons and electrons.
Elements named based on:
color, place of discovery, or a person. Also, each element has a unique atomic symbol, usually one/two letter abbreviation of the element is the bulk of atoms in the periodic table and the first is always capitalized. Some used for some elements based on alternate names. Reason that atomic symbols are totally different from names is because they have names from Latin or Greek origins of the names of those elements.
If we have 1 mole of each atom, it
does not look like there are the same number of atoms because there are different volumes. The reason is because of (same number of atoms, but not the same volume) density (how well the molecules/atoms compact together in a particular volume. Hg-very dense can compact a lot of things together. Zn - does not pack as well, more empty space) and the atoms are of different sizes. Great big atom takes a larger volume if it has 1 mole than if we had one mole of smaller atoms. Has to do with atomic size (different number of protons, neutrons, and electrons) and density
the subatomic particle that contributes the least to the mass of an atom
electron
matter consists of atoms which are made up of
electrons, protons, and neutrons. Protons and neutrons are in the nucleus, compact core, of an atom and electrons are dispersed in clouds around the nucleus. Atoms = mostly empty space
an atom is mostly
empty space. Farthest electron is going to be circling around the nucleus a large distance away
law of conservation of energy (Bohr model of the atom)
energy cannot be created/destroyed. Like mass
all atoms of a particular element
have the same number of protons in their nucleus. Number of protons in an atom's nucleus determines the element/identity of the element. If 1 proton, always Hydrogen. Might have diff neutrons and electrons, but if 1 proton, it is always Hydrogen. Does not depend on the number of neutrons and electrons.
Certain elements are
important for nutrition. Can look at choosemyplate.gov that tells you things you should be eating from a health standpoint. Eating better has a chemical basis because everything we eat is chemical. Made up of matter and compounds. The food we eat eventually becomes part of our body, so we want to put good things into it to get good things out of it
Protons, Neutrons and electrons differ
in charge too. Atomic nucleus = + charge. Cloud around nucleus = - charge. Opposite charges attract which is what holds the atom together. Similar electrical charges repel one another, which may seem odd because all positive in nucleus, but attribute clustering to "the strong force", attractive force that acts over short distances and is strong enough to overcome the repulsion of similar electrical charges
nuclear radiation
is the particles and energy released in a nuclear change. Treat cancer patients with this. High energy radiation that comes out of an atom when it undergoes a nuclear change
Proton
mass (g): 1.6726 x 10⁻²⁴ mass (amu): 1.0073 charge: 1+ location in atom: nucleus
electron
mass (g): 9.110 x 10⁻²⁸ mass (amu): 5.486 x 10⁻⁴ charge: 1- location in atom: outside the nucleus
Greek philosophers argued that
matter was composed of various combinations of the basic elements earth, air, fire, and water
for the 91 elements that occur naturally
more than 300 Isotopes have been identified. Over 1000 additional artificial Isotopes have been produced. Studies of naturally occurring in artificial isotopes have shown that some have unstable nuclei that spontaneously disintegrate to become more stable, releasing high-energy particles individual or groups of subatomic particles and or high-energy electromagnetic radiation. The particles energy releasing this nuclear change are called nuclear radiation, and atoms that emit nuclear radiation are called radioactive isotopes or radioisotopes. Radioisotopes emit nuclear radiation (high energy particles and electromagnetic radiation).
Until 1800
only 31 elements had been discovered, but today there are 91 elements occurring naturally, 114 have been given official names, and 3 more that have been produced, but not named. Total = 117 (changes year to year)
Matter can undergo
physical changes, chemical changes, and change to atomic nuclei. This nuclear change differs from the other two because atoms are altered during the process. Something new is created - when an atom's nucleus changes so does the identity of the atom.
Healthy diet should
provide sufficient amounts of protein, carbs, and fat. We have a lot of macro elements [eat these in larger quantities, proteins, carbs, fats, etc] (like Carbon). Also include adequate amounts of trace elements
USDA publishes
set of dietary guidelines to help people make healthy decision
Hydrogen emission spectrum (Bohr model of the atom)
taking a glass tube and pulling a vacuum on it to remove everything inside of it and fill it with Hydrogen gas in the sealed tube. Put electrodes (pieces of metal) on both ends and connect them to a power supply and apply very high voltage to it (such as 5000 V) to those electrodes. When we do that, the Hydrogen gas begins to glow and that glow comes out as light. If we send that light through a prism, it will split apart that light into different colors because that light has many colors. All light coming out is a mixture and prism separates the light out to various different colors. These colors can be shown as below for Hydrogen. These are the visible range of light we can see. 4 lines we can see with the naked eye.
atomic weight (periodic table of the elements)
the avg mass of the atoms of an element, as it is found in nature/ avg mass of the atoms in a naturally occurring sample of the element
Protons and neutrons have
the greatest mass, so mass of an atom mostly sits in the nucleus. Protons and neutrons in the nucleus and cloud around it is electrons (circling around the nucleus continually)
number of electrons carried by an atom can be determined from
the number of protons it has. Neutral atom (net charge = 0) contains equal amounts of protons and electrons.
average atomic mass =
the summation of all isotopes. Multiply the mass in AMUs or μ and fractional abundance (no units). Fractional abundance (between 0 and 100) differs from percent abundance because it has not been multiplied by 100. (Mass)(fractional abundance) + (mass)(fractional abundance) + (mass)(fractional abundance) etc = average atomic mass in AMUs or μ. WATCH SIG FIGS. Can check answers in periodic table. All atomic masses in periodic table is an average of all the isotopes If more of one isotope, the average atomic mass will be closer to that. This makes it a weighted average. More abundant an isotope, the more it will be weighed in the average calculation. More of one particular isotope, the more it will be weighed towards that isotope. Should be closer to higher abundance one's mass because greatest abundance
valence electrons
those in an atom's outermost occupied energy level. Electrons in the outermost shell. Important in predicting an element's properties. These electrons which are responsible for chemical bonding, how it behaves when it undergoes a chemical reaction, and how it reacts when it undergoes a chemical reaction. Can tell number based on group number in the periodic table. # of representative elements follows a periodic trend - 1A = 1 valence electron; 2A = 2 valence electrons, etc. In group 8A, however, helium has 2 valence electrons and the others have 8. Number of electrons in the outermost shell which helps us understand how it is going to react and behave. Group number tells the number of electrons in the outermost shell Correlations exist between the periods and energy levels. First period = energy level 1. 2nd = energy level 2, etc
Mass and charge are
two characteristics of subatomic particles. Mass is known, but it is very small and since this is inconvenient, mass of subatomic particles and atoms represented in atomic mass units (amu) or Daltons (after John Dalton). It is impossible to see the protons, neutrons, and electrons with the naked eye. When we have to deal with numbers that are extremely small, we develop a new scale. Created AMU for the particles, just another unit for mass. Very small unit of mass just like gram is on macro scale and AMU scale is very small on the micro scale
