Chapter 3.1 Compounds

Valence Valence electrons are the electrons in the outermost shell Valence Valence Valence Gain or lose? Gain or lose? Gain or lose?

Ions Cation Metals lose electrons There are now more protons (+) than electrons (-) = a Positive ion Anion Non-metals gain electrons There are now more electrons (-) than protons (+) = a Negative Ion

Examples What ion will these form? 11p+ 13p+ 17p+ Lose 1 e- = 10e- lose 3e- =10e- gain 1e- =18e- +1 ion +3 ion -1 ion

Compounds Compound = a substance made up of more than one kind of element. Chemical bonds = the links between two or more elements (atoms) and are what hold compounds together 2 types of compounds: Covalent compounds Ionic compounds

Ionic Compounds Atoms gain or lose electrons to form ions Give or accept electrons into the empty spaces in valence shells Non-metal + metal = ionic bond

Covalent Compounds Covalent compound = 2 or more non-metal elements Atoms combine by sharing electrons to form molecules

Molecules, Ions & Polyatomic Ions (P.A.I.) (poly = many) Polyatomic ions form when multiple non-metals come together Their names end in (-ate, –ite, -ium) Carbonate (CO3 2-) helps form egg shells. Phosphate (PO4 3-) helps form your bones and DNA. Ammonium (NH4+) and nitrate (NO3-) form fertilizer.

PAI are held together with STRONG COVALENT BONDS so they stick together! Never break them up! Think of them as a single charged ion (either positive or negative). They act like ions with other molecules and give/take electrons.

Common Polyatomic Ions Do not copy this table. Ammonium NH4+ Chlorate ClO3- Peroxide O2-2 Acetate CH3COO- Perchlorate ClO4- Chromate CrO4-2 Nitrate NO3- Permanganate MnO4- Dichromate Cr2O7-2 Nitrite NO2- Carbonate CO3-2 Silicate SiO3-2 Hydroxide OH- Sulfate SO4-2 Phosphate PO4-3 Hypochlorite ClO- Sulfite SO3-2 Arsenate AsO4-3 Chlorite ClO2- Thiosulfate S2O3-2 Arsenite AsO3-3 Cyanate CN- Thiocyanate SCN- Borate BO3-3 Bicarbonate HCO3- Bisulfate HSO4- Bisulfite HSO3-