Atomic Structure - Ryan Jones - Unit 7
Mass number:
(Not on the periodic table) - Tells the number of protons and neutrons in the nucleus of an atom (where most of its mass is located) Means add the protons and neutrons to get the mass #
Electron
(e^-) negative particle outside of the nucleus in the electron cloud
Neutron
(n^0) neutral particle in the nucleus with protons
Proton
(p*) positive particles in the nucleus
John Dalton (1803)
- Atom is a solid sphere that can't get any smaller - Elements are made of atoms that all have the same mass and compounds are atoms of different elements combined.
What hold it together?
- Attractive force between the (+) nucleus and (-) electron cloud Remember opposite electrical charges attract This is what holds the atom together - Repulsive force between (-) electrons Electrons want to be as far apart from each other as possible What gives the electron cloud volume - Repulsive force between (+) protons Protons want to be as far apart from each other as possible An insane amount of energy holds the nucleus together because of this
Nucleus
- Dense center - Made of protons and neutrons - Positively charged - Where the mass of the atom is located
Electron Cloud
- Space surrounding the nucleus - Broken down into regions of space called "shells" or "energy levels" - Electrons in shells further from the nucleus have the most energy - Electrons in the outermost energy level are called valence electrons - Negatively charged - Where the volume of the atom is located
Average Atomic Mass:
- Weighted average of all of the different versions of an element (called isotopes) - Closest to the most common isotope of the element Ex. The average atomic mass of Hydrogen is 1.01, therefore the most common version of hydrogen in nature is Hydrogen-1
Isotopes
- atoms of the same element with different numbers of neutrons. - Atomic # is same for both, mass # is different Ex. Hydrogen-1 vs. Hydrogen-2 - Most stable when number of p+ and n0 are the same.
Democritus
- first to name the atom - Atomus means indivisible in Greek and he thought that there was nothing smaller than an atom.
Atoms
- smallest unit particle of an element that still has the properties of that element.
Atomic number:
-Tells the number of protons or p+ in an atom of the element -Used to identify an element Periodic table arranged by these (thanks to Henry Moseley!) -In an electrically neutral atom, the # of p+ = the total # of e- Ex : Hydrogen - 1
JJ Thomson (1904) - Plum Pudding Model
-The atom is divisible - It is a positively charged sphere with negative particles embedded throughout
Describe the three forces that hold the nucleus together?
1. Attractive (Between Nucleus and electron cloud) 2. Repulsive Between electron (e-) -> Volume 3. Repulsive Between protons (p+) -> protons (p+)
What three forces hold an atom together?
1. Electromagnetic force 2. Strong nuclear force 3. Weak nuclear force
Questions from Class Crossword
1. My atomic number is 47 Answer: Silver 2. I have 26 protons. Answer: Iron 3. I have 6 valence electrons and 16 protons. Answer: Sulfur 4. I have 28 electrons when electrically neutral. Answer: Nickel 5. My average atomic mass is 35.453 Answer: Chlorine 6. I am the only metal that is a liquid at room temperature. Answer: Mercury 7. I am the only noble gas with 2 electrons. Answer: Helium 8. I am a halogen with 5 energy levels. Answer: Fluorine 9. I'm an alkaline earth metal used in fireworks. Answer: Magnesium 10. Eat me when you have cramps in your legs element. Answer: Potassium 11. I am not really an alkali metal but am in group 1. Answer: Hydrogen 12. I am a gas with 8 neutrons in my most common form. Answer: Oxygen 13. I am a metalloid that usually has 71 neutrons. Answer: Antimony 14. I am in the fifth period and the carbon family. Answer: Tin 15. I am very important for healthy teeth and bones. Answer: Calcium 16. I am the 2nd most reactive metal. Answer: Sodium
Aluminum Bohr Model
:)
periodic table
A chart of the elements showing the repeating pattern of their properties
Period
A horizontal row of elements in the periodic table
What does it mean for an atom to be electrically neutral?
A proton and an electron have an equal amount but an opposite type of charge. Thus, if an atom contains equal numbers of protons and electrons, the atom is described as being electrically neutral.
Periodic Table
A table organizing all of the elements known to exist by atomic number and chemical properties.
Symbol:
Abbreviation for the name of the element Ex : Hydrogen - H
To find Mass # :
Add Protons (p+) to Neutrons (n^0)
They are mostly reactive metals
Alkali metals
Groups: The vertical columns on the periodic table
All elements in the same group have the same number of valence electrons Remember: valence e- are the e- in an atom's outermost energy level in the electron cloud Group 1 = 1 valence e- Group 2 = 2 valence e- (skip the transition metals in groups 3-12) Group 13 = 3 valence e- (etc. until...) Group 18 = 8 valence e- With the exception of Helium Because of this, elements in the same group have similar chemical properties
Periods: The horizontal rows on the periodic table
All elements in the same period have the same number of energy levels in their electron cloud (e- means electrons) Remember: All atoms have a nucleus with p+ and n0 surrounded by an electron cloud with e-. Electron clouds are broken down into shells or energy levels, that each hold a certain number of e- Level 1 (closest to the nucleus): holds a max of 2 e- Level 2: holds up to 8 e- Level 3: holds up to 8 e- (for our purposes) Level 4: holds up to 18 e- (for our purposes)
A metalliod with 71 neutrons.
Antimony
Argon Bohr Model
Argon Bohr Model
Neils Bohr (1913)
Bohr Model : Electrons are negative particles that travel in fixed orbits around the positively charged nucleus that is made of positive protons and neutral neutrons
Bohr Model v.s. Electron Cloud Model
Bohr Model: a model of the atom in which electrons move rapidly around the nucleus in paths called orbits Electron Cloud Model: model of the atom in which the electrons seem to form a cloud as they move around the nucleus
Periodic Table Vocab.
Clues : 1. Symbol Au. Answer: Gold 2. The most reactive nonmetal. Answer: Fluorine 3. Atomic number of 12 Answer: Magnesium 4. An alkali metal in period 4. Answer: Potassium 5. The most abundant element in the air. Answer: Nitrogen 6. A metal with 3 valance electrons, used in cans. Answer: Boron 7. A period 3 element that will not react naturally. Answer: Argon 8. Has 5 valence electrons and is in period 3. Answer: Phosphorus 9. The most reactive metal. Answer: Cesium 10. A period 1 element used to make balloons float. Answer: Helium 11. The only nonmetal in group 1. Answer: Hydrogen 12. Responsible for the smell of rotten eggs. Answer: Sulfur 13. Has an atomic number that doubles silicons. Answer: Nickel 14. The first element in the group of rare metals. Answer: Lanthanum 15. A group of 12 metal that was once used in thermometers, but is now known to be poisonous. Answer: Mercury 16. Has 3 valence electrons and 4 energy levels. Answer: Boron 17. The only metalloid in period 3. Answer: Silicon 18. The only metalloid with 3 valence electrons. Answer: Boron 19. The alkali metal that makes up table salt. Answer: Sodium 20. It most common isotope has 5 neutrons. Answer: Boron
Atom and Periodic Table Vocab.
Clues : 1. The mass on the periodic table Answer: Average Atomic Mass 2. Region surrounding the nucleus where elctrons are found. Answer: Electron Cloud 3. Positively charged center of an atom. Answer: Nucleus 4. Particles that differ in number between isotopes Answer: Neutrons 5. Vertical colmuns in the perodic table. Answer: Group 6. Positively charged particles in an atom. Answer: Protons 7. Negatively charged particles in the outermost energy levels of the electron cloud. Answer: Valence electrons 8. Table that organizes the elements by properties. Answer: Periodic Table 9. Atoms of the same element have different masses. Answer: Isotopes 10. Smallest known particle that makes up protons and neutrons Answer: Quarks 11. All elements in the same one of these has the same nuber of energy levels in their electron cloud. Answer: Period 12. The smallest form of matter that still retains the properties of an element. Answer: Atom 13. Negatively charged particles in an atom. Answer: Electrons 14. The sum of protons and neutrons in an atom. Answer: Mass Number 15. Represents the identity of an element. Answer: Atomic Number
Neutrons (0)
Contributes to overall mass of atom
Dimitri Mendeleev (1869)
Developed the first periodic table of elements, organized by atomic mass
Henry Moseley (1913)
Discovered the number of protons is unique to each element (atomic number) and arranged the Periodic Table this way
valence electrons
Electrons on the outermost energy level of an atom
Find Atomics for Elements
Element Atomic # Mass # # of Proton Aluminum (Al) 13 27 13 Manganese (Mn) 25 55 25 Silver (Ag) 47 109 47 Boron (B) 5 11 5 Element # of Neutrons # of Electrons Aluminum (Al) 14 13 Manganese (Mn) 30 25 Silver (Ag) 62 47 Boron (B) 6 5
Atomic Calculations
Element Atomic # Mass # # of p+ # of n0 Lithium (Li) 3 7 3 4 Phosphorus (P) 15 31 15 16 Chlorine (Cl) 17 35 17 18 Nickel (Ni) 28 59 28 31 Potassium (K) 19 39 19 20 Element # of e- Lithium (Li) 3 Phosphorus (P) 15 Chlorine (Cl) 17 Nickel (Ni) 28 Potassium (K) 19
Explain why elements in the same group have similar properties.
Elements in the same group have similar properties because they have the same number of valence electrons in their outermost shell. Elements in the same period have different properties because the number of valence electrons in their outermost shells differ.
Metals
Elements that are good conductors of electric current and heat.
Nonmetals
Elements that are poor conductors of heat and electric current
Mettaloids
Elements that share some properties with metals and some properties with non-metals.
Magnesium : An element's location on the periodic table informs us about its atomic structure.
Example #1: Magnesium - Group 2 Therefore 2 valence electrons - Period 3 Therefore 3 energy levels
Are the most reactive nonmetals
Group 1
Group Names to Know:
Group 1 = Alkali metals Most reactive metals Note: For metals, reactivity increases as you move down the group Doesn't include Hydrogen Group 2 = Alkaline earth metals Group 3 = Rare earth metals Groups 3-12 = Transition metals Group 17 = Halogens Most reactive nonmetals Note: For nonmetals, reactivity decreases as you move down the group Group 18 = Noble Gases Nonreactiveelements, due to already being chemically stable
Hydrogen Bohr Model
Hydrogen Bohr Model
Isotope Notation
Hyphen form - Name of element - mass # Ex. Potassium - 40 This would be an atom of potassium with a mass number of 40 19 protons (because the atomic # is always 19 for potassium) 21 neutrons (40-19 = 21) Nuclear form - Mass #Symbol Ex. 40K Note: Nuclear notation can also include the atomic # below the mass #, but this isn't essential since the identity of the element allows you to determine the atomic #
Isotopes on Chart
Isotope Isotope Atomic # Mass # (Hyphen Form) (Nuclear Form) Uranium-235 235^U 92 235 Boron-10 10^B 5 10 Potassium-37 37^K 19 37 Boron-11 11^B 5 11 Silver-107 107^Ag 47 107 Uranium-238 238^U 92 238 Oxygen-17 17^O 8 17 Hassium-108 108^Hs 47 108 Element # of p+ # of n0 # of e- Uranium-235 92 143 92 Boron-10 5 5 5 Potassium-37 19 18 19 Boron-11 5 6 5 Silver-107 47 60 47 Uranium-238 92 146 92 Oxygen-17 8 9 8 Hassium-108 47 61 47
Isotope Name
Isotope Name Atomic # Mass # # of p+ # of n0 Carbon-12 6 12 6 6 13^C 6 13 6 7 Hydrogen-1 1 1 1 0 2^H 1 2 1 1 Lithium-6 3 6 3 3 7^Li 3 7 3 4 Isotope Name # of e- Carbon-12 6 13^C 6 Hydrogen-1 1 2^H 1 Lithium-6 3 7^Li 3
To find # of Neutrons :
It is the mass number + protons P.S. -- mass number = protons plus neutrons
To find # of protons :
It is the Atomic #
To find Atomic # :
Look on periodic table above symbol
Magnesium Bohr Model
Magnesium-26 Bohr Model
Classification of elements: All elements on the periodic table can be classified as metals, nonmetals, or metalloids
Metalloids: Solids Semi-conductors Physical properties like metals Chemical properties like nonmetals
Classification of elements: All elements on the periodic table can be classified as metals, nonmetals, or metalloids
Metals: Shiny, silvery solids Good conductors of heat and electricity Malleable and ductile Located to the left of the metalloids
A period 2 nonmetal with valence electrons.
Nitrogen
They don't react in nature
Noble gases
Classification of elements : All elements on the periodic table can be classified as metals, nonmetals, or metalloids
Nonmetals: Gases, or dull brittle solids Poor conductors Right of the metalloids With the exception of Hydrogen!
Oxygen-16 Bohr Model
Oxygen-16 Bohr Model
Ernest Rutherford (1911)
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus.
To find # of Electrons :
Same as protons (p+)
Electrons (-)
Surround the outermost part of the nucleus
Protons (+)
Surrounds the nucleus closer than the electrons do
Atomic structure
The atom consists of three component parts: Protons, Neutrons, and Electrons.
Struture of electron cloud
The modern model is also commonly called the electron cloud model. That's because each orbital around the nucleus of the atom resembles a fuzzy cloud around the nucleus, like the ones shown in the Figure below for a helium atom. The densest area of the cloud is where the electrons have the greatest chances of being
Erwin Schrödinger (1926)
The nucleus is surrounded by an electron cloud that is divided into shells, but electrons do not travel in fixed orbits
Group
a vertical column of elements in the periodic table
The number of protons and neutrons in an element?
atomic mass
Number of protons in an element?
atomic number
The identity of an element?
atomic number
Two isotopes of an element have same
chemical element
Volume of an Atom
electron cloud
Their atoms have 5 valence electrons
group 15
Two isotopes of an element have different
mass numbers - number of neutrons
Electron Cloud Model
model of atom in which the electrons seem to form a cloud as they move around the nucleus
Bohr Model
model of the atom in which electrons move rapidly around the nucleus in paths called orbits
The number of total electrons?
protons
Mass of an Atom
protons + neutrons
Nuclear notation
shows the atom's symbol, mass number, and atomic number (ignore the 11 and 1)
Bohr Model:
simple diagrams that show the atomic structure of an atom
Quarks
smaller particles that make up protons and neutrons
Element Names and Symbols
study quizlet
hyphen notation
the mass number is written with a hyphen after the name of the element
Shells
the orbits of electrons around the nucleus in certain energy levels
Electron Cloud
the subatomic particle located in the space surrounding the nucleus
