C1.1 - Fundamental Ideas

C1.1 - Fundamental Ideas

1. Atomic Structure

   • Everything is made of atoms

2. Atoms, Elements and Compounds

   • Everything is made of atoms
   • Elements contain 1 type of atom
     • some elements have different properties
   • compounds contain more than 1 type of atom
   • Atoms have their own symbols
     • symbols = international
     • Periodic table
       • column = group
       • Staircase = metals/non metal
   • Atoms, elements and compounds
     • compounds are joined by chemical bonds
     • atom has a nucleus (protons and neutrons) orbited by electrons

3. Atomic Structure

   • Particles
     • in the nucleus - protons (+1) and neutrons (0)
     • orbiting is electrons (-1)
     • Number of protons = number of electrons
       • balance charge
   • Atomic Number
     • bottom number
     • number of protons
   • Mass Number
     • protons plus neutrons
     • number of neutrons = mass number - atomic number

4. Arrangement of Electrons in Atoms

   • Shells/energy levels
     • lowest is closest to nucleus
   • 2,8,8,8 etc.
   • Electrons and the Periodic Table
     • groups have same number of electrons in highest energy level
     • Chemical properties depend on electrons
     • the less electrons in the highest shell, the more reactive

5. Forming Bonds

   • ionic bonding = transfers electrons
   • covalent bonding = shares electrons
   • when metal and non metal react they both become ions. Metal comes positive and non metal comes negative
   • Non metals form molecules bonding covalently
   • Chemical formulae show ratio. If we have Mg2+ and Cl- the formula is MgCl2 as we need 2 Cl to cancel charge

6. Chemical Equations

   • Reactants and products
   • mass of products = mass of reactants
   • Symbol equations are more useful than word equations
     • Not everyone speaks the same language
     • easily balanced