C1.1 : Chemical Concepts

The Atom
1. Nucleus
  1. Middle of the atom
  2. Protons (+ charge)
  3. Neutrons (neutral charge)
  4. Overall positive charge
2. Electrons
  1. Move around the nucleus in fixed orbits
  2. Negatively charged
  3. Occupy shells around nucleus
  4. Each shell has a fixed energy
3. Number of Protons= Number of electrons
4. Elements
  1. consist of one type of atom only
  2. ( number of protons in an atom decide what type of atom it is)
Periodic Table
1. Vertical columns=groups
2. Elements in the same group have the same number of electrons in their outer shells
3. Elements in the same group have similar properties
4. Element in the first column=group 0 (Noble gases)
5. Noble gases have full outer shells so they are stable
6. Mass number (top left) shows number of protons and neautrons
7. Atomic number (bottom left) shows number of protons
Electron Shells
1. Rules
  1. Electrons ALWAYS occupy shells
  2. The lowest energy levels are always filled first (ones closest to the nucleus
  3. 1st shell= 2 electrons
  4. Outer shells= 8 electrons
  5. Atoms are stable and don't react when they have full outer shells
  6. When the outer shell isn't full, atoms react to fill it
2. Electronic Structure
  1. Work out number of electrons (same as Atomic number)
  2. Work out how many electrons fill each shell (follow electron shell rules)
Compounds
1. Elements reacting and their atoms forming chemical bonds=Compounds
2. Making bonds= giving away, taking or sharing electrons
3. Only electrons are involved in bonding
4. Ionic Bonding
  1. Compounds made of a metal and non-metal are made of ions
  2. Metal atom LOSES electrons to make a positive ion
  3. Non-metal atom GAINS electrons to make a negative ion
5. Covalent bonding
  1. Compounds formed from non-metals consist of molecules
  2. Atoms SHARE electrons to fill outer shells
Forces between Particles
1. Solids
  1. Strong forces of attraction between particles=fixed positions=regular lattice arangement
  2. Particles don't move so solids have a definite shape/volume
  3. Particles vibrate-hotter solid means particles vibrate more so the solid expands
2. Liquids
  1. Some forces of attraction between particles=they're free to move past each other but tend to stick together
  2. Don't keep a definite shape and flow to fill bottom of container but keep same volume
  3. Constantly (randomly) moving, hotter liquids expand
3. Gases
  1. Next to no force of attraction between particles (travel in straight lines)
  2. No definite shape or volume
  3. Particles move randomly always. Expand when heated
4. Solutions
  1. Mixture of solvent (liquid) and solute (solid)
  2. Whether bond breaks depends on how strong the bonds are
  3. Bonds break, molecules mix

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C1.1 : Chemical Concepts

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