Chemistry Notes Essay

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The Elements and Periodic Table
The Atom * Contains protons and neutrons in the nucleus Atomic # * Electrons outside the nucleus in shells * Mass # = Protons + Neutrons Symbol * Atomic # = Electrons = Protons Atomic Weight * Mass # - Atomic # = Neutrons Name

The Periodic Table * Columns are called groups. There are 8 groups * Elements in the same group have the same properties * Rows are called periods. * 1st Group: Alkali Metals. Valency +1 * 2nd Alkali Earth Metals. Valency +2 * Transition Metals. All have valency of +2 except Silver (Ag) =+ 1 * 3rd Group. Valency +3 * 4th Group. Valency +- 4 * 5th Group. Valency -3 * 6th Group. Valency -2 * 7th Group are called the halogens. Valency -1 * 8th Group are called the Noble or Inert gases. They have a full outer shell and do not have a valency because they do not need to gain or lose electrons * Di- Atomic Gases= N2, O2, F2, Cl2, Br2, I2. When they occur by themselves they occur in pairs. * All elements to the left of the dark zig zag line are metals. However the ones on the border are metalloids. Elements to the right are non-metals
* A group of chemical compounds which contain the element hydrogen. * Are always an aqueous solution * React with metals to produce hydrogen gas * Neutralise alkali’s or bases (Hydroxide) * React with carbonate to produce Carbon Dioxide, can be tested by making limewater milky * Have characteristics with universal indicator and litmus paper * Sour Taste * When they dissolve in water they dissociate or break apart to form a special hydrogen ion in solution * Proton donors * Any H+ is an acid * HNO3 (Nitric Acid) Nitrate NO3 (Salt) * H2SO4 (Sulphuric Acid) Sulphate SO4 (Salt) * H2CO3 (Carbonic Acid) Carbonate CO3 (Salt) * H3PO4 (Phosphoric Acid) Phosphate PO4 (Salt) * HCl (Hydrochloric Acid) Chloride Cl (Salt) * HBr (Hydrobromic Acid) Bromide Br (Salt) * HF (Hydrofluoric Acid) Fluoride Fl (Salt) * CH3COOH (Acetic Acid) Acetate CH3COO (Salt)
* Produce OH- ions * Proton acceptors * Bitter taste * Their aqueous solution conduct an electric current * React with acid to form salts and water * OH (Hydroxide) * NH3 (Ammonia) * NH4 (Ammonium)
* Contain CO32- ions. * React with acid to form salts, carbon dioxide and water

General Chemical Equations
Combustion: Element + Oxygen Element Oxide
Simple Decomposition or synthesis: Element A + Element B Compound AB (Synthesis) Compound AB Element A + Element B (Decomposition)
Acids on Active Metals: Acid + Active Metal Salt + Hydrogen (H2)
Acids on Carbonates: Acid + Carbonate Salt + Carbon Dioxide (CO2) + Water (H2O)
Acids + Base: Acid + Base Salt + Water
Water with Very Active Metals: Metal + Water Hydrogen + Metal Hydroxide
Acids + Metal Oxide: Acid + Metal Oxide Salt + Water
Precipitation: Soluble Salt soln 1 + Soluble Salt soln 2 Precipitate (s) + Soluble Salt soln 3

Naming Chemical Equations
Metal and Non- Metals: 1. Name the metal 2. Name the non-metal ending in “ide”

2 Non- Metals: 1. Name the first non-metal and a prefix for the second 2. Name of the second element ends in “ide” 3. If the first element has greater than 2 atoms also use a prefix.

Metals and Complex Compounds: 1. Name the metal 2. Name the complex compound

Balancing Chemical Equations 1. Start with the largest compound 2. Balance complex ions first 3. Do other elements 4. Carbon, Hydrogen, Oxygen in that order 5. Odd and even number, double up and start again

Writing Formulas

1. Write down the symbols required 2. Get the valency’s 3. Cancel down to simplest whole number 4. Cross over