Chemistry

• Group 1


  Alkali Metals
• Group 2


  Alkaline Earth Metals
• Group 7


  Halogens
• Group 8/0


  Nobel Gases
• An element is a substance made up of only 1 type of atom.
• In the periodic table, metals are below staricase and no-metalsare above.
• All metals can conduct electricity.
• Non-metals with the exception of carbon, in the form of graphite, do not conduct.
• Alkali metals are different to typical metals, they are soft, have a lower density and low melting and boiling points.
• However, alkali metals do share a few properties common to all metals. They are shiny and are good conductors of heat and electricity.
• Alkali metals react quickly with water to produce an alkali solution and hydrogen gas.
• Sodium + Water -> Sodium Hydroxide + Hydrogen
• Alkali metals are so reactive that they must be stored under oil. The re-activeness of the metals increases as we go down the group.
• Elements are made up of tiny particles called atoms. All the atoms of one element are the same.
• Different elements are made up of different atoms.
• Atoms are made up of 3 subatomic particles -

  • Protons
  • Neutrons
  • Electrons
  • (Nucleus - centre of an atom)
• Proton


  Location - nucleus
• proton - mass


  1
• proton - charge


  1+
• neutron - location


  nucleus
• neutron - mass 


  1
• neutron - charge


  0
• electron - location 


  inside the electron shell
• electron - mass


  0 "negligible"
• electron - charge


  1-
• The atomic no. tells you how many protons are in the atom. In an atom, proton number and electron numbers are equal.
• Atoms are overall equal because they have the same amount of positive protons and negative electrons.
• Electron shells/ 'energy levels'

  2,8,8 rule
• 1st shell can hold max, 2 electrons
• 2nd can hold - max 8
• 3rd can hold max 8 as well
• A full outer shell -

  • this makes the atom stable
  • stable so will not react 'nonreactive'
• No full outer shell so it will be reactive.
• Only protons and neutrons have mass (electrons are negligible).
• Mass number = no. of protons + no. of neutrons
• We can use the mass number to work out the number of neutrons.
• No. of Neutrons = Mass - no. of protons

  OR/

  No. of Neutrons = Mass number - atomic number
• Nuclide notation is used to show the symbol, atomic number and mass number of atoms, from which number of -

  • Protons
  • Electrons
  • Neutrons can be determined
• Nuclide Notation

  p=2

  e=2

  n=4-2=2

  
• Isotopes are atoms of the same element with the same number of protons but different number of neutrons.

  OR/

  Isotopes are atoms of the same element with the same atomic number but different mass number.