The Chemist’s Shorthand: Atomic Symbols - Element Symbols - Neon - Ne - Chlorine - Cl - Nitrogen -N-N-N-N

The Chemist’s Shorthand: Atomic Symbols - Oxygen -O-O-O-O - Silicon - Si - Zinc - Zn

The Chemist’s Shorthand: Atomic Symbols - Gold - Au - Lead - Pb - Sodium - Na - Iron - Fe

The Chemists’ Shorthand: Formulas Chemical Formula: Symbols = types of atoms Symbols = types of atoms Subscripts = relative numbers of atoms Subscripts = relative numbers of atoms CO 2 Structural Formula: Individual bonds are shown by lines. Individual bonds are shown by lines. O=C=OO=C=OO=C=OO=C=O

The Chemists’ Shorthand: Formulas A molecule contains four phosphorus atoms and ten oxygen atoms. P 4 O 10 A molecule contains one aluminum atom and three chlorine atoms. AlCl 3

The Mass and Change of the Electron, Proton, and Neutron

The Chemists’ Shorthand: Atomic Symbols K  Element Symbol Mass number  Atomic number 

IsotopesIsotopes Atoms with the same number of protons but different numbers of neutrons. K-39 and K-40 Na-23 and Na-24 H-1, H-2, and H-3

Periodic Table Elements classified by: - properties - properties - atomic number - atomic number Groups (vertical) 1A = alkali metals 1A = alkali metals 2A = alkaline earth metals 2A = alkaline earth metals 7A = halogens 7A = halogens 8A = noble gases 8A = noble gases Periods (horizontal)

Periodic Table Transition metals MetalsNonmetals Semimetals (Metalloids)

IonsIons Cation: A positive ion Mg 2+, NH 4 + Anion: A negative ion Cl , SO 4 2 

IonsIons Mg 2+ # of protons and electrons 12 protons and 10 electron Mg -> Mg e - Lost 2 electrons

IonsIons K+K+K+K+ # of protons and electrons 19 protons and 18 electron K -> K + + e - Lost 1 electron

IonsIons Cl  # of protons and electrons 17 protons and 18 electron Cl + e - -> Cl - Gained 1 electron

IonsIons O  # of protons and electrons 8 protons and 10 electron O + 2e - -> O 2- Gained 2 electrons

Writing Formulas for Ionic Compounds 1. Na + and S 2- Na 2 S Na 2 S 2. Ca 2+ and P 3- Ca 3 P 2 Ca 3 P 2 Ionic Compounds: Net Charge of Zero

Naming Compounds 1. Cation first, then anion 2. Monatomic cation = name of the element Ca 2+ = calcium ion 3. Monatomic anion = root + -ide Cl  = chloride CaCl 2 = calcium chloride Binary Ionic Compounds:

Naming Compounds NaCl sodium chloride AlF 3 aluminum fluoride MgBr 2 magnesium bromide Binary Ionic Compounds:

Naming Compounds - When metal forms more than one cation - use Roman numeral in name PbCl 2 Pb 2+ is cation PbCl 2 = lead (II) chloride Binary Ionic Compounds:

Naming Compounds CuCl copper(I) chloride CuBr 2 Copper(II) bromide FeF 3 iron(III) fluoride Binary Ionic Compounds:

Naming Compounds - Compounds between two nonmetals - Second element is named as if it were an anion. - Use prefixes - Never use mono- for the first element. P 2 O 5 = diphosphorus pentoxide Binary molecular compounds:

Naming Compounds P2O5P2O5P2O5P2O5 diphosphorus pentoxide CCl 4 carbon tetrachloride Binary compounds:

Naming Compounds N2O3N2O3N2O3N2O3 dinitrogen trioxide SCl 6 sulfur hexachloride Binary compounds:

Polyatomic Ions to Memorize NO 3 – Nitrate ion NO 2 - Nitrite ion

Polyatomic Ions to Memorize SO 4 2- Sulfate ion SO 3 2- Sulfite ion

Polyatomic Ions to Memorize CO 3 2- Carbonate ion HCO 3 - bicarbonate or hydrogen carbonate ion

Polyatomic Ions to Memorize PO 4 3- Phosphate ion

Polyatomic Ions to Memorize NH 4 + Ammonium ion

Compounds with Polyatomic Ions K 2 SO 4 potassium sulfate NaNO 3 sodium nitrate

Compounds with Polyatomic Ions K 2 CO 3 potassium carbonate Na 3 PO 4 sodium phosphate

Writing Formulas from Names Disulfur dichloride S 2 Cl 2 Potassium oxide K2OK2OK2OK2O calcium phosphate Ca 3 (PO 4 ) 2

The Mole The number equal to the number of carbon atoms in exactly 12 grams of pure 12 C. 1 mole of anything =  units of that thing

Avogadro’s number equals  units

Molar Mass A substance’s molar mass (molecular weight) is the mass in grams of one mole of the compound. A substance’s molar mass (molecular weight) is the mass in grams of one mole of the compound. CO 2 = x CO 2 = x = grams per mole = grams per mole

Molar Mass How many moles of CaCl 2 are in a 10.0 g-sample of CaCl 2 ? The molar mass of CaCl 2 is g/mole. How many moles of CaCl 2 are in a 10.0 g-sample of CaCl 2 ? The molar mass of CaCl 2 is g/mole. Moles = mass x (1/molar mass) Moles = mass x (1/molar mass) = 10.0 g x (1 mole / g) = 10.0 g x (1 mole / g) = = = mole (3 sig figs) = mole (3 sig figs)

Molarity (M) concentration expressed as moles of solute per liter of solution. concentration expressed as moles of solute per liter of solution. M = moles of solute/L of solution M = moles of solute/L of solution Moles of solute = Molarity (M) x L of solution Moles of solute = Molarity (M) x L of solution L of solution = moles of solute/Molarity (M) L of solution = moles of solute/Molarity (M)

Molarity (M) Calculate the molarity of a solution prepared by dissolving 65.5 g of solid NaCl in enough water to make 4.50 L of solution. Calculate the molarity of a solution prepared by dissolving 65.5 g of solid NaCl in enough water to make 4.50 L of solution. M = moles of solute/L of solution M = moles of solute/L of solution Moles of NaCl = mass x (1/molar mass) Moles of NaCl = mass x (1/molar mass) Molar mass of NaCl = = g/mole Molar mass of NaCl = = g/mole Moles of NaCl = 65.5 g x (1 mole/ g ) Moles of NaCl = 65.5 g x (1 mole/ g ) = moles = moles Molarity = moles/4.50 L = M Molarity = moles/4.50 L = M

Chemical Equations Chemical change involves a reorganization of the atoms in one or more substances.

Chemical Equation A representation of a chemical reaction: C 2 H 5 OH (l) + O 2 (g)  CO 2 (g) + H 2 O (g) C 2 H 5 OH (l) +3O 2 (g)  2CO 2 (g) +3H 2 O (g) reactants products reactants products

To Balance a Chemical Equation Start with the most complicated molecule. Use the smallest integers for the coefficients. Never change the chemical formula (subscripts)

Balance the following Chemical Equation Li(s) + Cl 2 (g) -> LiCl(s) 2Li(s) + Cl 2 (g) -> 2LiCl(s)

Balance the following Chemical Equation Ca(s) + HCl (aq) -> CaCl 2 (aq) + H 2 (g) Ca(s) + 2HCl (aq) -> CaCl 2 (aq) + H 2 (g)

Balance the following Chemical Equation C 12 H 22 O 11 (s) + __O 2 (g) -> __CO 2 (g) + __H 2 O(g) C 12 H 22 O 11 (s) + 12O 2 (g) -> 12CO 2 (g) + 11H 2 O(g)