Module 6

pure substances

comprised of a single species of matter and are not a mixture.

elements

made up of a single type of atom

compounds

substances where two or more different types of atom that have been chemically bonded together

ionic bonds

electrons are transferred from one atom to another and comprise of a metal and nonmetal

ions

each will have a charge associated to them based on whether they have gained or lost electrons

Main group elements

elements in the same group will gain and lose the same number of electrons

Ex: Chlorine and Argon

chlorine has 7 valance electrons and needs to gain 1 electron to be similar to Argon to form the cl- anion

Ex: Magnesium and neon

Magnesium needs to lose 2 electrons to be similar to that of neon forming a positive mg2+ cation

Oxidation states

transition metals may have several different types of cations with different charges

Transition metal positive charge

-Iron (III)= Fe3+

-Copper(I)= Cu+

What do metals tend to form

cations by losing electrons

What do nonmetals tends to form

anions by gaining electrons

Lattice

when an ionic compound forms, the individual ions of each element are arranged in a repeating structure of cations and anions

ratio of cation and anion

-in an ionic compound the ratio of anions and cations will vary depending on the charge. Important to note that when these ions combine, the result must be a neutral species

formula unit

Chemical formula of an ionic compound will represent the lowest possible ratio of cations and anions

Covalent bonds

electrons are shared from between atoms and these occur between two nonmetals

ate

ion with more oxygen

ite

ion with less oxygen

Type 1 Naming for ionic compounds

-name of cation

-base name of anion + ide (if monatomic)

Type 2 naming for ionic compounds with transition metals

-name of cation + (roman numeral)

-base name of anion + ide

Type 1 Naming for ionic compound with polyatomic ions

-name of cation

-name of polyatomic ion

Naming binary covalent compounds: Lower group number named first

-prefix

-name of 1st element

-prefix

-base name of 2nd element

Acids

compounds in which hydrogen is bonded to either a nonmetal, known as binary acids or a polyatomic oxyganion, known as oxoacids

Type 1 naming for binary acids

-hydro

-base name of anion + ic and acid

Type 2 Name for oxoacids ending in ate

-base name of oxyacid

-replace suffix ending in -ate to -ic acids

Type 2 naming for oxoacids ending in ite

-base name of oxyacids

-replace the suffix ending in -ite, to ous acid

Law of definite proportions

-states that the ratio of each type of atom in a substance is the same throughout that entire substances and is unique to that compound,

-this means that for a compound such as carbon dixoide, regardless of the amount of carbon dioxide we have we will always ahve the same mass ratio of oxygen to carbon

mass fraction

mass A

---

mass total

mass %

mass A/ mass total x 100%

Empirical formula

the simplest formula, which is defined as the smallest whole number ratio of each element in a compound

molecular formula

represents the actual number of each atom in a molecule of that compound

hydrogen peroxide

Empirical formula= HO

molecular formula= H2O2

combustion analysis

a known mass of the unknown compound is burned in excess oxygen to produce co2, h2o and other products based on composition, by measuring the mass of these products we can determine the masses of each element in the unknown element

(g)

gas

(l)

liquid

(s)

solid

(Aq)

aqueous solution (dissolves in water)

stoichiometric coefficients

large numbers located to the left of the chemical formula