Chapter 7 Chemical Formulas and Chemical Compounds

Significance of Chemical Formula

used for ionic or covalent compounds
tells the element(s) involved
tells the number of each atom in amolecule
or ratio of each atom in a formula unit

+1, +2, +3, +1, +2, and +1

Group 1, Group 2, Al, NH+4, Zn and Cd, along with Ag

Group 1

+1 Charge

Group 2

+2 Charge

Group 17

-1 Charge

Group 16

-2 Charge

Group 15

-3 ONLY REFERS TO NITROGEN AND PHOSPHORUS

Stock System

refers to roman numeral is the charge (Transition metals and metals under the staircase)

Nomenclature

must have unique name for each compound
several catergroies with rules
Ionic (cation always certain charge)
ionic (cation has various charges)
Covalent - Not acid (prefixes inolved

(When H is first element)
Covalent - acid- binary (2 elements Hydrogen, root-root-ic-acid
Covalent - acid - oxyacid - Hydrogen -oxygen
Acid not dissolved or dissolved

Cation

anion - die
Do not change name of polyatomic
cation (roman numberal) variable
Charge anion - ide *do not change name of poly

Roman Numerals

I, II, III, IV, V

Percent Composition

parts/whole * 100
percent composition (by mass) gives percentage by mass of each element in a compound

Empericial Formula

the smallest whole-number ratio of each type of atom in a compoudn, not the specific number of each type of atom in amolecule (simplest reduced ratio)

Molecular Formula

always a whole-numer multiple of the empericial formula (how compound actually exists in nature)