Chemistry - periodic table

• Why is group 1 called the Alkali metals?

  When added to water they react to form an alkaline solution.
• What happens to the reactivity as you go down group 1

  it increases
• Physical properties of group 1 metals

  low density

  low melting point

  malleable

  conducts heat and ekectricty
• Why does reactivity increase as you go down group 1?

  - all group 1 elements have to lose 1 electron

  - the outer electron is further away from the attraction of the nucleus

  - easier to lose the electron
• Transition metals


  groups 3-12
• properties of transition metals

  useful as catalysts

  form different ions

  strong and hard

  not very reactive

  high density

  compounds coloured
• what is todays periodic table arranged jn

  atomic number
• what happens to the reactivity as you go down group 7 (halogens)

  it decreases
• why does the reactivity decrease as you go down group 7 (halogens)

  - all of group 7 needs to gain 1 electron

  - as you go down the group the atoms have more shells

  - therefore the attraction of the nucleus to the electron is weaker
• properties of halogens


  are diatomic molecules

  low density

  brittle as solids

  insulators

  low melting points
• What are diatomic molecules?

  2 atoms joined tofether
• diatomic elements


  Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Chlorine, Bromine
• which group are the noble gases

  Group 0 (last one)
• what is special about the electron structure of the noble gases

  They have a full outer shell of electrons
• describe the chemical reactivity of the noble gases

  they are not reactive because of their full outer shell and don't need to gain or lose an electron
• differences between the modern periodic table and mendeleev's

  - groups go across and periods go down in mendeleevs

  - no group 0 in mendeleevs

  - transition metals mixed in with group 2 and now they are between groups 2 and 3
• metals


  elements that react to form positive ions
• non metals


  Elements that do not form positive ions
• How do group 1 elements react with water

  - release hydrogen and form hydroxides

  - reacts vigorously

  - water fizzing
• Lithium reaction with water

  Fizzes steadily, gradually disappears
• Sodium reaction with water

  Fizzes rapidly, melts into a ball and disappears quickly
• Potassium reaction with water

  Ignites with sparks and a lilac flame, disappears very quickly
• similarities of potassium and lithium reaction with water

  - metal hydroxide formed

  - metal floats