Chemical formulas: represent the number of atoms of each element in a compound

Atom: the base unit of any element, smallest piece of an element that still has the qualities of the element

Ions: charged atoms [see my note “isotopes and ions” for more details]

• Cation: positively charged atoms/ions (typically metals)

• Anion: negatively charged atoms/ions (typically nonmetals)

See my note “Isotopes and Ions” if you do not understand what these charges mean:

Group 1: 1+ charge

Group 2: 2+ charge

Group 3 - Group 12 (excluding 13, 30, and 47) + 31, 32, 49, 50, 51, 81, 82, 83, 84, 113, 114, 115, 116: transition metals with various charges

Group 18 (excluding the transition metals): no charge

Group 17 (excluding the transition metals): 1- charge

Group 16 (excluding the transition metals): 2- charge

Group 15 (excluding the transition metals): 3- charge

Group 14 (excluding the transition metals): either 4+ or 4- charge

Polyatomic Ions: groups of covalently bonded atoms that have a charge [see my note on common polyatomic ions]

Ionic Compound: contain a cation (metal) and an anion (nonmetal)

Molecule: two or more atoms (usually nonmetals) that are covalently bonded

Diatomic molecule: elements that in their natural form are only found in molecules of two atoms. For example: oxygen is only found as O2, you will only find oxygen alone in chemical reactions

• the 7 diatomic molecules are : H, O, N, Cl, Br, I, F

Binary compounds: compounds of only 2 elements (Ex: H2O, CO2)

Binary Type I: Ionic Compound Containing one cation and one anion both with known charges (no transition metals except Al, Zn and Ag)

Binary Type II: Ionic Compound Containing one cation and one anion with the cation being any transition metal except Al, Zn, and Ag

Binary Type III: Covalent Molecular Compound Containing two nonmetals, doesn’t have a charge

Ternary Compounds: compound containing 3 or more elements

How to name

Binary type I:

• “cation” “root of anion” “ide”

• CaCl2 (1 Calcium + 2 Chlorine) = Calcium Chloride

• If we see Calcium Chloride written we know that because Calcium has a +2 charge and Chlorine only has a 1- then there must be two Chlorines for the charges to balance out and be neutral (see my note “paper notes on compounds”)

Binary type 2:

• because the cation is an element than can have various charges, it’s important to mention what the charge this sample of it has

• FeO (in which the iron has a charge of +2) = Iron (II) Oxide

• we use the Roman numerals in parentheses to show the charge on the cation

Ternary:

• if the ternary compound is something like “cation + compound with negative charge” or “compound with positive charge + anion” you name it very similar to a Binary type I or II compound.

• The first element or compound is just that element/compound’s name (following the rules of marking the charges as shown in Binary type II if needed)

• If the second element or compound is a compound, then you just add the compound’s name

• If the second element or compound is an element, then you just add the root of the element’s name + “ide” (like Binary Type I)

• Na(CO4) [Sodium + Chlorate] = Sodium Chlorate

• Fe(CO4)3 [Iron (III) + Chlorate] = Iron (III) Chlorate

• (NH4)Cl [Ammonium + Chlorine] = Ammonium Chloride

Binary type 3:

• Because binary type 3 compounds are not ionic, they do not have a charge

• Since we cannot figure out how many of each element there are based on their charges, we use Greek prefixes to note how many of each

• for example: C2O would be DIcarbon MONoxide

• we do not use the prefix “mono” if the first element in the compound only has one of it, the “mono” would just be implied (CO2 is Carbon Dioxide, not monocarbon dioxide)

Greek Prefixes:

1. mono

2. di

3. tri

4. tetra

5. penta

6. hexa

7. hepta

8. octa

9. nona

10. deca