Chemistry Y10

• Cations, which are positively charged ions are one of the 2 types of ions that can exist in ionic compounds. Although you can use the periodic table to determine the charge for elements with a specific group number, you must remember some for those which don't:

  • Hydrogen is H+
  • Copper is Cu2+
  • Silver is Ag+
  • Ammonium is NH4+
  • Zink is Zn2+
  • Lead is Pb2+
  • Rusty Iron is Fe3+
  • Green Iron is Fe2+
• Anions, which are negatively charged ions are one of the 2 types of ions that can exist in ionic compounds. You must remember these:

  
  

  NOTE: Oxygen is added in some of these compounds that tend to end in ate/oxide.

  • Hydroxide Ion is OH-
  • Nitrate is NO3-
  • Carbonate is CO3^2-
  • Sulfate is SO4^2-
  • Oxygen is O^2-
• Explain means to state how and why something happens, so one can fully understand.
• To work out the chemical formula of ionic compounds, you need to:

  1. Use it's valency (which you can get from the periodic table), and write down the valency below the element's symbols.
  2. Cross multiply the elements
  3. Write out the chemical formula, and simplify if necessary to the simplest ratio (ionic is always empirical formula)
• To work out the chemical equation of covalent compounds, you can simply add them.
• A chemical formula describes elements in a compound or molecule and the relative proportions of those elements. E.g C6H12O6, O2.
• A chemical equation relates the change undergone by itself or more formulas to create product formulas.
• Chemical formulas aren’t for metallic compounds (non-metal + non-metal); they’re an alloy.
• A chemical equation relates: Products → Reactants. The equation is balanced on both sides; atoms aren’t created or destroyed, they just reassemble themselves into new products. E.g O2 + 2H2 → 2H2O.