CH 100 Chapter 3

The total number of valence electrons can vary between:

1 and 8.

protons + electrons

=mass number

excited state

A state in which an atom has a higher potential energy than it has in its ground state. An atom in the excited state is not stable. *When it returned back to ground state, it releases the energy that had previously gained, often in the form of electromagnetic radiation but it can also be released via heat.

Which of the following is an aluminum ion? Remember the octet rule! Al2+ Al+ Al3+ Al

Al3+

What is the first column named?

Alkali metals The alkali metals are lithium, sodium, potassium, rubidium, cesium, and francium. Hydrogen is unique in that it is generally placed in Group 1, but it is not a metal. The compounds of the alkali metals are common in nature and daily life. One example is table salt (sodium chloride); lithium compounds are used in greases, in batteries, and as drugs to treat patients who exhibit manic-depressive, or bipolar, behavior. Although lithium, rubidium, and cesium are relatively rare in nature, and francium is so unstable and highly radioactive that it exists in only trace amounts, sodium and potassium are the seventh and eighth most abundant elements in Earth's crust, respectively.

What is the second column named?

Alkaline metals The alkaline earth metals are beryllium, magnesium, calcium, strontium, barium, and radium. Beryllium, strontium, and barium are rare, and radium is unstable and highly radioactive. In contrast, calcium and magnesium are the fifth and sixth most abundant elements on Earth, respectively; they are found in huge deposits of limestone and other minerals.

Ion

An atom or group of atoms that has a positive or negative charge. As in it is not neutral, with an equal number of neutrons and protons.

What wavelength range of light is visible to the naked eye?

Between 380-760 nm.

A bit about Bohr's atomic Model

Bohr explained that electrons can be moved into different orbits with the addition of energy. When the energy is removed, the electrons return back to their ground state, emitting a corresponding amount of energy - a quantum of light, or photon. This was the basis for what later became known as quantum theory. This is a theory based on the principle that matter and energy have the properties of both particles and waves. It accounts for a wide range of physical phenomena, including the existence of discrete packets of energy and matter, the uncertainty principle, and the exclusion principle. Bohr explained that electrons can be moved into different orbits with the addition of energy. When the energy is removed, the electrons return back to their ground state, emitting a corresponding amount of energy - a quantum of light, or photon. This was the basis for what later became known as quantum theory. This is a theory based on the principle that matter and energy have the properties of both particles and waves. It accounts for a wide range of physical phenomena, including the existence of discrete packets of energy and matter, the uncertainty principle, and the exclusion principle. Bohr's work had a strong influence on our modern understanding of the inner workings of the atom. However, his model worked well for an explanation for the emissions of the hydrogen atom, but was seriously limited when applied to other atoms. Shortly after Bohr published his planetary model of the atom, several new discoveries were made, which resulting in, yet again, a revised view of the atom

Which of these is a chloride ion? Remember the octet rule! Cli Cl Cl+ Cl-

Cl-

In Bohr's Model of the atom when an electron gains or losses energy it will:

Electrons remain in the in the shells until they absorb or emit a quantum of energy. When it gains energy, it will move further away from the nucleus to a higher energy level. Upon emission of energy, the electron will fall back to the lower energy level.

How many protons and electrons will a neutral elements?

Equal number depending on the elements.

semi-metals/metalloids

Exhibit properties intermediate between those of metals and nonmetals.

Which columns are called the main group elements?

First two and last six columns.

Discontinous Spectra:

If the light emitted from the excited atoms is viewed through a prism, then individual patterns of lines will be produced. These lines are called spectra and correspond to fingerprint wavelengths (symbol for wavelength is λλ ) for a specific element. The image illustrates how the light from excited electrons can be diffracted to produce line spectra for the elements of hydrogen, helium, and iron. The specific elements produce wavelengths within the visible spectrum (between 400-700 nm) and can be seen by the naked eye. In order to obtain the numerical wavelengths (in nanometers), one would need to employ some type of detector. When light from a hydrogen gas discharge tube is passed through a prism, the light is split into four visible lines. Each of these spectral lines corresponds to a different electron transition from a higher energy state to a lower energy state. Every element has a unique atomic emission spectrum, as shown by the examples of helium (He)(He) and iron (Fe)

Why will metals always tend to loose electrons for form cations?

Metals have a less likely chance to gain electrons because it is easier to lose their valance electrons and form cations.

Does visible light and radiation cause cancer?

No Visible light and radiation on the right side of the electromagnetic spectrum has longer wavelengths and does not have the potential to ionize tissues and/or DNA. Visible light (labeled IR). microwave, and radio waves are classified as being nonionizing radiation and have not been linked to cancer.

What is the name of the following ion? Remember to add ion after the name. O2-

Oxide ion

energy levels (shells)

Possible orbits that an electron can have in the electron cloud of an atom.

Naming Isotopes other than hydrogen:

Put the mass number after the name of the element. For most elements other than hydrogen, isotopes are named for their mass number. For example, carbon atoms with the usual 6 neutrons have a mass number of 12 (6 protons + 6 neutrons = 12), so they are called carbon-12. Carbon atoms with 7 neutrons have atomic mass of 13 (6 protons + 7 neutrons = 13). These atoms are the isotope called carbon-13.

Cell phones are an example of what ind of waves?

Radio waves

Which columns contain the transition metals?

The 10 column block between the main group element columns.

Valence electrons:

The electrons in the outermost shell (main/highest energy level) of an atom; furthest from the nucleus; these are the electrons involved in forming bonds. The valence shell is also where atoms can gain or loose electrons to become more stable. When electrons return to a lower energy level, they emit energy in the form of light. Using a modified Bohr model the first shell can only contain 2 electrons, while all shells can hold 8 electrons. This model only works on elements 20 and under.

ground state

The lowest energy state of an atom. The ground state of an atom is the lowest energy state of the atom. When those atoms are given energy, the electrons absorb the energy and move to a higher energy level. These energy levels of the electrons in atoms are quantized, meaning again that the electron must move from one energy level to another in discrete steps rather than continuously.

mass number (atomic mass)

The mass number is the mass of the atom, a unit called the atomic mass unit (amu). It is 1/12 the mass of a carbon-12 atom Atomic mass units (amu) are useful, because, as you can see, the mass of a proton and the mass of a neutron are almost exactly 11 in this unit system. A neutron has just a tiny bit more mass than a proton, so its mass is often assumed to be one atomic mass unit as well. Because electrons have virtually no mass, just about all the mass of an atom is in its protons and neutrons. Therefore, the total number of protons and neutrons in an atom determines its mass in atomic mass units.

Periodic Table of Elements:

The periodic table is an arrangement of elements in order of increasing atomic number.

Emission spectrum:

The unique pattern of light given off by an element when it is given energy.

Excited state:

To be in a higher energy level. A state in which an atom has a higher potential energy than it has in its ground state.

Nonmetals are

Upper right. *Nonmetals are generally brittle and poor electrical conductors. *Metals and non-metals are separated by a diagonal band of metalloids.

Can heat and electrical current be used to excite atoms?

Yes. Atoms can gain energy to interm-34duce these transitions from various sources. The gases in the image have been excited with the use of electrical current. The atoms in each of these noble gases produce distinctive colors that can be used to identify the elements . Each of these species contains a different number of electrons that can undergo different types of excitations. In turn, each gas produces a signature color. Fireworks are similar to flame test experiments. Firework manufacturers select certain metal atoms to produce desired colors for these devices. Individual detonators will explode the metal compounds to emit radiant colors of light.

A rainbow is an example of what spectrum?

a continuous spectrum

The electromagnetic spectrum is an example of what kind of spectrum?

a continuous spectrum.

Every element can be classified as either a metal or:

a nonmetal, or a metalloid (or semi metal, elements between metals and non-metals).

How are atoms identified?

atomic number, name and/or one/two letter symbols. Don't forget the atomic number = the number of protons in an element. Because elements are pure substances that make up all matter, if you change the number of protons then you also change the element.

Isotopes are

atoms of the same element that have a different number of neutrons *this changes the mass number mass number - atomic number = number of neutrons

If an element is located on the left side of the periodic table (metal) and has less than three valence electrons, it will loose it'a valence in order to:

become stable and achieve an octet. In contrast, elements on the right side of the table (nonmetals) will gain up to eight electrons to achieve octet status.

Ionizing

ejects electron, causing ions to form -higher frequency, higher-energy, electromagnetic radiation is ionizing.

Which of the following changes in order for ions to form? neutrons electrons protons photons

electrons

When electrons return to a lower energy level, they emit:

energy in the form of light.

A neutral atom must have

exactly one electron for every proton because the positive charge of a proton is equal in magnitude to the negative charge of an electron.

nonionizing

excites atoms but does not ionize them -Lower frequency, lower-energy electromagnetic radiation is nonionizing.

Next to last column on the periodic table is...

halogens The halogens are fluorine, chlorine, bromine, iodine, and astatine. The name halogen is derived from the Greek words for "salt forming," which reflects that all the halogens react readily with metals to form compounds, such as sodium chloride and calcium chloride (used in some areas as road salt). Compounds that contain the fluoride ion are added to toothpaste and the water supply to prevent dental cavities. Fluorine is also found in Teflon coatings on kitchen utensils. Although chlorofluorocarbon propellants and refrigerants are believed to lead to the depletion of Earth's ozone layer and contain both fluorine and chlorine, the latter is responsible for the adverse effect on the ozone layer. Bromine and iodine are less abundant than chlorine, and astatine is so radioactive that it exists in only negligible amounts in nature.

Hydrogen Isotopes ie:

hydrogen, deuterium, tritium Most hydrogen atoms have just one proton and one electron and lack a neutron. These atoms are just called hydrogen. Some hydrogen atoms have one neutron as well. These atoms are the isotope named deuterium. Other hydrogen atoms have two neutrons. These atoms are the isotope named tritium.

Elements that have similar chemical properties are grouped...

in columns called groups or families.

Atoms of the same element that differ in their numbers of neutrons are called:

isotopes Many isotopes occur naturally. Usually one or two isotopes of an element are the most stable and common. Different isotopes of an element generally have the same physical and chemical properties. That's because they have the same numbers of protons and electrons.

Metals are

located on the left of the periodic table. They are lustrous, good conductors of electricity, and readily shaped (they are ductile and malleable).

A shorthand notation for describing the composition of an atom/element:

mass number upper subscript, atomic number lower subscript before the chemical symbol Another way to refer to a specific atom is to write the mass number of the atom after the name, separated by a hyphen. The Cr atom would be written as chromium-52.

Electrons are

negatively charged (-1) and fall in orbital paths around the nucleus Electrons are one of three main types of particles that make up atoms. They are very small and contribute virtually no mass. For perspective if electrons were the mass of a penny, a proton or a neutron would have the mass of a bowling ball. They are fundamental particles that do not consist of smaller particles. They are a type of fundamental particle called leptons. All leptons have an electric charge of -1 or 0. All atoms have the same number of electrons as protons so the positive and negative charges cancel out, making atoms electrically neutral. Because opposite electric charges attract each other, negative electrons are attracted to the positive nucleus. This force of attraction keeps electrons constantly moving through the otherwise empty space around the nucleus.

Anions

negatively charged ions

Neutrons are

neutrally charged - electrically neutral - zero charge they do not really interact with protons or electrons other than being bound into the nucleus with the protons

last column of periodic table are the...

noble gases The noble gases are helium, neon, argon, krypton, xenon, and radon. Because the noble gases are composed of only single atoms, they are called monatomic. At room temperature and pressure, they are unreactive gases. Because of their lack of reactivity, for many years they were called inert gases or rare gases. However, the first chemical compounds containing the noble gases were prepared in 1962. Although the noble gases are relatively minor constituents of the atmosphere, natural gas contains substantial amounts of helium. Because of its low reactivity, argon is often used as an unreactive (inert) atmosphere for welding and in light bulbs. The red light emitted by neon in a gas discharge tube is used in neon lights.

Each row of the periodic table is called a...

period *Periods have different lengths; the first period only has 2 elements (hydrogen and helium). Period 1 = 2 elements Period 2 and 3 = 8 elements in each Period 4 and 5 = 18 elements each later periods are so long that a segment from each is removed and placed beneath the main body of the table.

Protons are

positively charged articles found in the nucleus of the atom. Have a positive electrical charge of one (+1) and a mass of 1 atomic mass unit (amu). Together with neutrons, they make up virtually all of the mass of an atom.

Cation

positively charged ion. More protons then electrons. ie: Pt (Platnum) has 78 protons and we are told for this example it has 74 electrons. This would create a positive charge of 4 (Pt with a subscript in the upper right of 4+.

Quantized:

requiring or possessing specific amounts of energy

The two rows beneath the main body of the periodic table contain:

the inner transition metals. The elements in these two rows are also referred to as, respectively, the lanthanide metals and the actinide metals.

Atomic number:

the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. *Protons equal the number of positive charges because they are positively charged. However all atoms are neutral in electrical change so the atomic number also tell you how many electrons the atom has. 1 to 1 ratio to be neutral. *to change the number of protons is to change the element.

Radioactive decay:

the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element Stability (or lack) of Isotopes - Atoms need a certain ratio of neutrons to protons to have a stable nucleus. Having too many or too few neutrons relative to protons results in an unstable, or radioactive, nucleus that will sooner or later break down to a more stable form. A process called radioactive decay. Many isotopes have radioactive nuclei, and these isotopes are referred to as radioisotopes. When they decay, they release particles that may be harmful. This is why radioactive isotopes are dangerous and why working with them requires special suits for protection. The isotope of carbon known as carbon-14 is an example of a radioisotope. In contrast, the carbon isotopes called carbon-12 and carbon-13 are stable.

In many cases, elements that belong to the same group (vertical column) on the periodic table form ions with the same charge because:

they have the same number of valence electrons. For example, all ions made from alkali metals, the first column on the periodic table, have a 1+ charge. Ions made from alkaline earth metals, the second group on the periodic table, have a 2+ charge. On the other side of the periodic table, the next-to-last column, the halogens, form ions having a 1− charge. The image shows how the charge on many ions can be predicted by the location of an element on the periodic table.

Ground state:

to be in the lowest energy level possible.

Areas of light that possess short wavelengths are located where on the electromagnetic spectrum?

to the left of the spectrum. All wavelengths from UV (ultraviolet) to γγ (gamma) range have the potential to ionize tissues and/or DNA. As a result, individuals who have been exposed to large amounts of these types of radiation in acute time periods could develop cancer. Pic shows the different areas of light (or electromagnetic spectrum).