Cheatography
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Contains Valance Electrons, Compounds, Bonding - Why? etc.
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Review
Valance Electron: Group Number. |
Compound: A substance composed of two or more elements in fixed, definite proportions. |
Forming Ions
Atoms of metals have few valance electrons (1-2) thus they tend to lose electrons to form a positive ion (cations). |
Atoms of non-metals have many valance electrons (4-7) thus they tend to gain electrons to form negative ions (anions). |
They do this to become stable in their outer shell. |
Ionic Bonding: Type I
Format: |
Name of Cation (metal) |
Base Name of Anion (non-metal) + ide |
Example: |
NaCl |
Sodium Chloride |
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MgBr2 |
Magnesium Bromide |
Roman Numerals
1 = I |
3 = III |
5 = V |
7 = VII |
2 = II |
4 = IV |
6 = VI |
8 = VIII |
Ionic Bonding: Type II
Format: |
Name of Cation (metal) |
(Charge of cation (metal) in roman numerals) |
Base name of Anion (non-metal) + ide |
Example: CuCl |
Copper |
(I) |
Chloride |
CuCl2 |
Copper |
(II) |
Chloride |
VSEPR Theory
VSEPR: |
A theory based on the idea that electron groups (lone pairs, single bonds, or multiple bonds) repel each other. |
Drawing the Lewis Structure/Bonding
Step One: |
Draw the lewis structure for each covalent compound. |
Step Two: |
Identify the bonds as single, double, or triple. |
Step Three: |
Label the bonding and non-bonding electrons. |
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Bonding - Why?
Octet Rule: Atoms bond in such a way as to obtain a full outer shell (8). |
Bonding involved valance electrons only. |
In general, atoms either transfer or share electrons to obtain a full outer shell (8). |
Valance electrons are responsible for the chemical properties of an atom. |
Ionic Bonding: Dot and Cross
Naming Compounds: Nomenclature
Is it Ionic? (Metal + One or more non-metals) |
If so go to Type I and Type II. |
OR |
Is it Covalent? (All non-metals) |
If so go to Type III. |
Electron Groups
To determine the shape of a molecule, count only electron groups around the central atom. |
Each of the following is consider one electron group: |
Non-Bonding Pair - (A lone pair of electrons) |
Bonding Electrons - (single, double, or triple) |
Example: CH4 has 4 electron groups (4 single bonds, 0 lone pairs) |
Drawing Molecular Geometries
Straight Line: |
Bond in plane of paper. |
Hashed Line: |
Bonding going into paper. |
Wedge: |
Bond coming out of the paper. |
Terms
Single Bond: |
One pair of electrons shared between two atoms (Cl2) |
Double Bond: |
Two pairs of electrons shared between two atoms. (O2) |
Triple Bond: |
Three pairs of electrons shared between two atoms. (N2) |
Bonding Electrons: |
Electrons shared between atoms. |
Non-Bonding Electrons: |
Electrons only found on one atom. (Lone pairs) |
Overall: |
Draw the lewis structure and determine how they will bond with one another to have full outer shells (8). |
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Identify the bonding and non-bonding electrons. |
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Summary
Ionic Bonding: |
Covalent Bonding: |
Metal + One or more non-metals. |
All non-metals. |
Electrons are transferred. |
Electrons are shared. |
Ions are formed. |
Ions are not formed. |
Ex. NaHCO3 or NaCl |
Ex. F2 or CO2 |
Prefixes
1 = Mono |
3 = Tri |
5 = Penta |
7 = Hepta |
9 = Nona |
2 = Di |
4 = Tetra |
6 = Hexa |
8 = Octa |
10 = Deca |
Covalent Bonding: Type III
Format: |
Prefix |
Base name element 1 |
Prefix |
Base name of element 2 + ide |
Example: N2O |
Di |
nitrogen |
Mono |
xide |
IF3 |
--- |
Iodine |
Tri |
Fluoride |
B2H8 |
Di |
boron |
Octa |
hydride |
CS2 |
--- |
Carbon |
Di |
sulfide |
Drawing Lewis Structures (2 Atoms or more)
Step One: |
Draw the lewis structure for each atom separetly. |
Step Two: |
The atom that has the most unpaired electrons is the central atom. |
Step Three: |
The other atoms will share electrons with the central atom. |
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