Structure Of Matter (P. 40-60) 25%

Front 1

Groups (families) & Periods

Back 1

-The 18 vertical columns of the table are called groups or families, while the seven horizontal rows are called periods and correspond to the seven principal quantum energy levels, n=1 through n=7.

Front 2

Metals

Back 2

-malleable, ductile, and have luster; most of the elements on the periodic table are metals. They oxidize (rust and tarnish) readily and form positive ions (cations). They are excellent conductors of both heat and electricity. The metals can be broken down into several groups.

Front 3

Transition Metals (Transition Elements)

Back 3

-known for their ability to refract light as a result of their unpaired electrons.
-have several possible oxidation states.
-Ionic solutions of these metals are usually colored, so these metals are often used in pigments.
-The actinides and lanthanides are collectively called the RARE EARTH ELEMENTS and are filling the f orbitals. They are rarely found in nature.
-Uranium is the last naturally occuring element; the rest are man-made.

Front 4

Nonmetals

Back 4

-lie to the right of the staircase and do not conduct electricity well b/c they do not have free electrons.
-All the elemental gases are included in the nonmetals.
-Notice that hydrogen is placed with the metals b/c it has only one valence electron, but it is normal.

Front 5

Alkali Metals (1A) [Metal Family]

Back 5

-the most reactive metal family, these must be stored under oil b/c they react violently with water!
-They dissolve and create an alkaline, or basic, solution, hence their name.

Front 6

Alkaline Earth Metals (2A) [Metal Family]

Back 6

-These also are reactive metals, but they don't explode in water; pastes of these are used in batteries.

Front 7

Halogens (7A) [Nonmetal Family]

Back 7

-Known as the "salt former," they are used in modern lighting and always exist as diatomic molecules in their elemental form.

Front 8

Noble Gases (8A) [Nonmetal Family]

Back 8

-Known for their extremely slow reactivity, these were once though to never react; neon, one of the noble gases, is used to make bright signs.

Front 9

ATOMIC RADIUS (p. 42)

Back 9

-is measured by calculating the distance b/w the 2 nuclei of atoms when they are involved in a chemical bond.
-ATOMIC RADII DECREASE MOVING ACROSS A PERIOD FROM LEFT TO RIGHT: as you increase the number of protons in the nucleus of the atom, you increase the EFFECTIVE NUCLEAR CHARGE of the atom (Zeff), and the nucleus pulls more strongly on the entire electron cloud.
-ATOMIC RADII INCREASE MOVING DOWN A GROUP (FAMILY):as we move down a family, the attractive force of the nucleus dissipates as the electrons spend more time farther from the nucleus (Bohr Model).
-When an atom loses an electron, a CATION, or positive ion, is formed.
-For negatively charged ions, or ANIONS, the nuclear attractive force decreases (and there is enhanced electron-electron repulsion), so the electrons are less tightly held by the nucleus.
-If comparing the sizes of 2 atoms that are ISO-ELECTRONIC (have the same number of electrons, consider the number of protons the two atoms posses.) -see example on bottom of page.

Front 10

Ionization Energy (IE) (p. 43)

Back 10

-the energy required to remove an electron from the atom in the gas phase.
-first atom requires energy; each subsequent atom requires even more energy (2nd IE > 1st IE).
-Differ due to shell: it takes less energy to remove a p electron than an s electron, even less energy to extract a d electron, and the least energy to extract an f electron.
-IONIZATION ENERGY INCREASES AS WE MOVE ACROSS A PERIOD.
-IONIZATION ENERGY DECREASES AS YOU MOVE DOWN A GROUP (FAMILY).
-SHIELDING: occurs when the inner electrons in an atom shield the outer electrons from the full charge of the nucleus. The phenomenon is only important as you move down the periodic table!

Front 11

Electron Affinity (p. 44)

Back 11

-the amount of energy release when an electron is added to the atom in its gaseous state-when an electron is added to an atom, the atom forms a negative ion.
-Most often, energy is RELEASED as an electron is added to an atom, and the greater the attraction b/w the atom and the electron added, the more negative the atom's electron affinity.
-ELECTRON AFFINITY BECOMES MORE NEGATIVE AS WE MOVE ACROSS A PERIOD.
-Important exceptions to this rule are the noble gases: He, Ne, Ar, Kr, and Xe. They have electron affinities that are positive (meaning very low), b/c if they were to accept another electron, that electron would have to go into a new, higher, energy subshell, and this is energetically unfavorable.
-ELECTRON AFFINITIES DO NOT CHANGE VERY MUCH AS YOU GO DOWN A GROUP.
-Remember that there is no clear trend for electron affinity as you go down a group on the periodic table-this fact could come up in a synthesis of knowledge question!

Front 12

Chemical Bond

Back 12

-is the result of an attraction b/w atoms or ions.
-The types of bonds that a molecule contains will determine its physical properties, such as melting point, hardness, electrical and thermal conductivity, and solubility.

Front 13

How do Chemical Bonds Occur?

Back 13

-Only the outermost, or VALENCE, electrons of an atom are involved in chemical bonds.
-EX: when 2 hydrogen atoms approach each other, electron-electron repulsion and proton-proton repulsion both act to try to keep the atoms apart. However, proton-electron attraction can counterbalance this, pulling the 2 hydrogen atoms together so that a BOND is formed.
-All of the noble gases have eight valence electrons (s2p6) and are very chemically stable, so this phenomenon is known as the OCTET RULE.

Front 14

Ionic Bond (Type Of Chemical Bond)

Back 14

-electrons transferred from less electronegative atom to more.
-Electro-negativity > 1.67
-Ex: NaCl

Front 15

Covalent Bond (Type Of Chemical Bond)

Back 15

-electrons shared b/w atoms.
-Non Polar: 0 - 0.4
-Polar: 0.4 - 1.67
-Ex: CO2

Front 16

Metallic Bonds (Type Of Chemical Bond)

Back 16

-exist only in metals, such as aluminum, gold, copper, and iron.
-responsible for the unique properties of metals, such as their high conductivity.

Front 17

Molecular Shape

Back 17

-The most important thing to remember based on its chemical formula and the basic premises of the VSPER MODEL is that the molecule will assume the shape that most minimizes electron pair repulsions.
-Electrons can exist in BONDING PAIRS, which are involved in creating a single or multiple covalent bond, or NONBONDING PAIRS, which are pairs of electrons that are not involved in a bond, but are localized to a single atom.

Front 18

Molecular Polarity

Back 18

-refers to an uneven distribution of electron pairs b/w the two bonded atoms.
-Molecules can be polar (dipole).
-Dipoles: are molecules that have a slightly positive charge on one end and a slightly negative charge on the other.
-However, molecules can also contain polar bonds and not be polar. Carbon dioxide is a perfect example. Both of the C-O bonds in Co2 are polar, but they're oriented such that they cancel each other out, and the molecule itself is not polar.

Front 19

Hybrid Orbitals

Back 19

-result from a blending of atomic orbitals (s and p orbitals) to create orbitals that have energy that's in b/w the energy of the lone orbitals.
-see hybridization chart (p. 60)

Front 20

Pi Bond

Back 20

-result from the sideways overlap of p orbials, and pi orbitals are defined by the region above and below an imaginary line connecting the nuclei of the two atoms.
-these never occur unless a sigma bond has formed first, and they may form only if unhybridized p orbitals remain on the bonded atoms.
-they occur when sp or sp(2) hybridization is present on central atom but not sp(3) hybridization.