The Periodic Table

The Periodic  Table - history, alkali metals, halogens, transition elements

HideShow resource information
  • Created by: LAura
  • Created on: 01-04-11 22:48

Brief History

Past ways of ordering elements: 

  • Physical/Chemical properties
  • Relative atomic mass

1864 - John Newlands tries to arrange elements in his law of octaves. His method is ignored as inconsistencies were found as he progresses.

1869 - Dmitri Mendeleev expands on Newland's Octaves. Gaps are left for undiscovered elements and discovered elements are ordered by atomic mas

1 of 5



Based on electronic structure.

Elements within the same group have similar properties - same amount of electrons in outer shell.

Larger atoms lose electrons more freely, and gain them less freely - due to the electrons in question being further away from the nucleus.

Group 1 - reactivity increases further down the group;the single electron in the outer shell is less attrcted due to the amount of space between electron and nucleus. The atom is lost more freely.

Group 7 - reactivity decreases further down the group; the electron needed to complete the outer shell is less easily attracted due to the weaker attraction.

2 of 5

Group 1 - The Alkali Metals

  • Silvery Solids
  • Hydroxides dissolve in water to give an alkaline solution
  • down group one, the alkali metals become:
    • bigger
    • more reactive
    • denser
    • lower bp/mp
  • very reactive.
  • Lithium, Sodium, Potassium, Rubidium, Caesium and Francium
  • one outer electron
  • reaction with water produces hydrogen gas
  • always form ionic compounds
3 of 5

Group 7 - The Halogens

The halogens become less reactive with higher mp/bp as you go down the group.

Non-metals with coloured vapours:
Flourine - very reactive, poisonous
Chlorine - fairly reactive, poisonous, dense
Bromine - dense poisonous red-brown volatile liquid
Iodine - dark grey crystalline solid or purple vapour

Bond covalantly and ionically

Form +1 ions when bonded with metals

They react with metals to produce salts

4 of 5

The Transition Elements

  • Good conductors of heat and electricity
  • dense, strong, hard - more so than group 1
  • unreactive with water and oxygen
  • less reactive than group 1
  • colourful compounds
  • often make good catalysts
  • form more than one ion (+3, +2)
5 of 5


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all The Periodic Table resources »