Chemical Names and Formulas

Molecules The smallest electrically neutral unit of a substance Oxygen

Molecular Compounds Atoms of different elements combine chemically to form compounds Water

Ions Atoms or groups of atoms that have a positive or negative charge. An ion forms when an atom or group of atoms loses or gains electrons

Cations and Anions Cations form ions by losing one or more electrons Remember, electrons are negative. If you lose a negative you become more positive Anions form ions by gaining one or more electrons Remember, electrons are negative. If you gain a negative you become more negative

Ionic Compounds Compounds composed of cations and anions. Cations are classified as metals and anions are classified as non-metals.

Chemical Formulas Shows kinds and numbers of atoms in the smallest representative unit of the substance Monatomic elements are represented by their atomic symbols If there is more than one element a subscript is used

Molecular Formulas Shows the kinds and numbers of atoms present in a molecule of a compound Molecular formulas show the composition of the molecule but does not tell you the molecule’s structure

Formula Unit Lowest whole-number ratio of ions in a compound NaCl 1:1 MgCl2 1:2

Law of Definite Proportions In samples of any chemical compound, the masses of the elements are always in the same proportions If you had 100g of magnesium sulfide and break it down into its elements, you will always obtain 43.13g of magnesium and 56.87g of sulfur

Law of Multiple Proportions Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in ration of small whole numbers H2O O 1 H2O2 O 2

Monatomic Ions

Classic Names of Monatomic Ions Copper (I) Cuprous Copper (II) Cupric Iron (II) Ferrous Iron (III) Ferric Lead (II) Plumbous Lead (IV) Plumbic Tin (II) Stannous Tin (IV) Stannic

Polyatomic Ions -ite endings have 1 less oxygen atoms than the –ate endings

Binary Compounds Compounds composed of two elements. Cation goes first Anion is second with the ending replaced with –ide Overall charge must be zero

Ternary Compounds Compound that contains atoms of three different elements Usually contain a polyatomic ion

Binary Molecular Compounds Composed of two nonmetallic compounds Use prefixes to tell how many atoms are in the compound Mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-

Naming Common Acids