Rules for Sig. Digs
All digits from 1-9 are sig.
Zeroes btwn the digs. 1-9 are sig.
Leading 0’s ≠ sig.
If there is NO decimal pt, trailing 0’s are sig.
If there is a decimal pt, trailing 0’s are sig.
When + and – round to lowest sig. dig.
Period
A row in the periodic table
Group
A column in the periodic table
Valence Electrons
Electrons in the outermost shell of an atom
Nomenclature
Ionic Compounds
Write symbols for each element
Write charge for element above its symbol
Cross the numbers from the charges over to the other element to make a subscript
Change the ending to “-ide”
Latin Names
Iron= Ferric/Ferrous
Copper= Cupric/Cuprous
Tin= Stannic/Stannous
Gold= Auric/Aurous
Mercury= Mercuric/Mercurous
Lead= Plumbic/Plumbous
Polyatomic Compounds
*Recognize the groups of atoms that act as one ion*
OH NICK the CAMEL had a CLAM for SUPPER in PHOENIX
*exception Ammonium*
Molecular Compounds
Use prefixes
Mono-1
Di-2
Tri-3
Tetra-4
Penta-5
Hexa-6
Hepta-7
Octa-8
Non-9
Deca-10
Element closest to the left goes first
Scientific Notation
Notation based on powers of 10
Sig. dig. X 10# of times decimal moved
Exponent Examples
3 • 43 = 192
4x3 • 2x3 = 8x6
x5 • x3 = x8
65/63 = 62
x4/x7 = x-3 = 1/x3
80 = 1
(y4)3 = y12
Matter

Pure Substance
A material that is composed of only one type of particle
Mixture
A material system made up of two or more different substances which are mixed but are not combined chemically
Element
Primary constituents of matter
Compounds
Consists of two or more different atoms
Homogenous
A homogeneous mixture is any mixture that is uniform in composition throughout
Heterogeneous
A heterogeneous mixture is any mixture that is not uniform in composition
Diagrams
Lewis Dot
Element symbol and valence electrons
Bohr Rutherford
In the nucleus (#of neutrons, #of protons)
Electrons circling in shells

Periodic Trends


Atomic Radius
The distance from the centre of the atom to the boundary within which electrons spend 90% of their time

Trends in A.R within a Period
The radius increases going from left to right
Trends in A.R within a Group
Size of radius increases going down a group
Ionization Energy
The amount of energy required to remove the outermost electron from the atom or ion in a gaseous state
Electronegativity
An indicator of the relative ability of an atom to attract shared electrons
Trends in E.N
E.N increases going up a group
E.N increases going left to right across a period
Highest E.N: Fluorine
Lowest E.N: Francium
Metal Reactivity Trend
Moving left to right across a period reactivity increases
Moving down a group reactivity decreases
Metallic Properties Trend
Tend to decrease across a period and increase down a group
Atomic #
The number of protons
Atomic Mass
The mass of an atomic particle
Isotope
An atom with different numbers of neutrons
Ion
An atom that has gained or lost an electron
Trends in Electron Configuration
Elements in the same group have the same # of valence electrons
Across a period # of valence electrons increase
Valence electrons in a period occupy the same energy level
Down a group the energy of the valence shell electrons increases
Covalent Bond Angle Summary
IV V VI VII
4 bonds 3 bonds 2 bonds 1 bond









Ionic Bonds
Between a metal and a non-metal
High melting and boiling points
Conductive when liquid
Covalent Bonds
Between 2 non-metals
Low melting and boiling points
Poor Conductivity
Soft or brittle solid forms
Noble Gases
Group 18 elements
Full octet
Does not bond
Stable, non- reactive
Halogens
Group 17 elements
7 valence electrons
Reactive
Non-metals
Alkali Metals
Elements in group 1 (except for hydrogen)
1 valence electron
Very reactive
Alkaline Earth Metals
Elements in group 2
2 valence electrons
Semi reactive
Lanthanides
Period 6
Rare earth elements
Inner transition elements
Actinides
Period 7
Have no stable isotopes
Radioactive
Transition Metals
Groups 3 through 11
Hard metals
High melting points
Complex electron configuration
Non-metals
Semi reactive
Most common in the tissue of living organisms
Metalloids
Share properties of metals and non-metals
Poor conductors
Polarity
The physical alignment of atoms
Can be predicted using the electronegativity difference of the elements that are bonded
Polar Covalent
Unequal sharing
Nonpolar Covalent
Equal sharing
Metallic Bonding
Occurs between atoms with low electro negativities
Close-packed lattice formation
No electron belongs to one atom
Metallic bonds are not ions, but nuclei with moving electrons
Physical Properties of Metallic Bonds
Conductive
Lustrous
Malleable
The greater the amount of valence electrons the stronger the metallic bond
VSEPR Theory
V: Valence
S: Shell
E: Electron
P: Pair
R: Repulsion
Because of negative charges, atoms orient themselves as far apart as possible


Electron Affinity
The energy absorbed or released when an electron is added to a neutral atom
The Octet Rule
When bonds form between atoms, the atoms gain, lose, or share, electrons in such a way that they create a filled outer shell containing eight electrons
Single Bond
A covalent bond that results from atoms sharing one pair of electrons
Double Bond
A covalent bond that results from atoms sharing two pairs of electrons
Triple Bond
A covalent bond that results from the atoms sharing three pairs of electrons
Bonding Pair
A pair of electrons that is shared by two atoms, thus forming a covalent bond
Lone Pair
A pair of electrons that is not part of a covalent bond
Electronegativity Difference
The difference between the electro negativities of two atoms
0: Pure nonpolar