Module 1 chemistry

• Proton

  • Relative Mass - 1
  • Relative charge - +1
• Neutron


  • Relative Mass - 1
  • Relative charge - 0
  • Behaviour in strong electric field - No Effect
• Electron


  • Behaviour in strong electric field - Deflection towards (+) positive plate
• Mass number

  The number of protons plus neutrons in the nucleus of an atom
• Isotopes

  • Atoms with the same atomic number but different mass numbers
• Relative atomic mass


  The weighted average mass of naturally occurring atoms of an element on a scale
• What does Dalton theory say? All matter is made up of tiny particles called atoms
• State the 4 properties of the Dalton theory?

  1. Atoms of different elements have different mass 2. Atoms of the same element are identical. 3. Atoms of different elements can combine to more complex compounds. 4. Atoms can not be broken down further
• Alpha (a)


  Mass number 4 units & nuclear +2 charge
• Gamma rays


  Have no charge
• Radioactivity


  Is the spontaneous breakdown of an unstable nucleii by Emission of alpha, beta and gamma ray particles .
• Helium nuclei


  Positively charged particles (protons)
• Electrons (-)


  Negatively charged particles
• Very high frequency


  Electromagnetic radiation
• Mass


  Measure of the amount of matter in an object
• Radiation


  • Alpha:Stopped by thin sheet paper
  • Beta: Stopped by thick aluminium sheet
  • Gamma: Stopped by thick lead sheet
• Mass number


  Same for proton converted to neutron, atomic number decreases by 1
• Radioactive isotopes


  • Argon-37
  • Helium-4
• Uses of radioactive isotopes 


  • Search in faults pipeline,
  • medicine for radiotherapy
• Atomic orbital


  Region of space where there is a high probability of finding an electron
• Shapes of atomic orbitals

  • S-orbital
  • P-orbital
• Electronic configuration


  Shows the electrons occupying particular atomic orbitals
• Order of filling atomic orbitals


  • 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 5s, 5p, 5d
• Factors affecting first ionisation energy

  • Size of nuclear charge
  • Distance of outer electrons from nucleus
  • Shielding by inner shell electrons
• Forces of attraction


  • Strong attractive force
  • Weak intermolecular forces but strong intramolecular bonds
  • Weak intermolecular forces but strong intramolecular bonds
  • Very weak
• Covalent bonding


  Force of attraction between nuclei of neighbouring atoms sharing a pair of electrons with non metal atom
• Sigma bonds


  Formed by overlap of atomic orbitals along a line between the two nuclei
• Pi bonds


  Formed by sideways overlap of atomic orbitals
• Ionic bonding


  Electrostatic force of attraction between oppositely charged ions
• Metallic bonding


  Chemical bond between atoms in a metallic element or alloy
• Van der Waals forces this attraction are not permanent . All atoms and molecules including noble gas atoms
• Hydrogen bonding


  Special form of permanent dipole bonding involving H atom covalently bonded to F, O or N atom
• Coordinate (dative covalent) bonding


  Formed when one atom provides both electrons for the covalent bond
• Bond energy


  Amount of energy needed to break one mole of a particular bond in 1 mole of gaseous molecule
• Oxidation is the gain of oxygen or loss of electrons.
• Reduction is the gain of electron(s) from a substance, resulting in the loss of oxygen and the formation of a reduced substance
• what is a reducing agent?

  Carries out reduction and is oxidized
• When ionic compounds react, only some of the ions take part in the reaction. The ions that play no part in the reaction are called spectator ions.
• Writing ionic equations


  1. Write the full balanced chemical equation

  2. Write the charges on those substances which are ionic

  3. Cancel the spectator ions

  4. The ionic equation is that which remains
• Rate


  Rate = (x final - x initial) / (t final - t initial)