Periodic table

• Alkali Metals in water:

  Alkail metal + Water --> Alkali metal hydroxide + Hydrogen
• Why does boiling point decrease as you go down group 7: Atomic mass has increased, more energy is needed to break bonds
• Why are group 1 metals more reactive as you go down the group:

  As you go down the group, outer electron gets further away from the nucleus. The force of attraction between the nucleus and the outer electron decreases so the electron is lost easier.
• Why does reactivity decrease as you go down group 7: Outer electrons is further away nucleus which means more electron shells, which means more shielding meaning it is harder to gain 1 electron.
• Group 1 + Group 7 --> Group 1 Group 7 ide
• Why are light bulbs which have metal filaments that get very hot when switched on are filled with Argon instead of air:

  Argon is unreactive which helps prevent the filament from heating up and burning quickly.
• How chlorine is more reactive than bromine using a solution of chlrorine water and solution of potassium bromide salt:

  1. This is a displacement reaction -> chlorine will dsiplace the bromine from the salt solution.
  2. The chlorine will be reduce to chlorine ions .
  3. The bromide ions will be oxidised to become bromine.
  4. The bromine will turn the solution orange.
• Why did Mendeleeve leave gaps in his periodic table:

  1. For elements tha haven't been discovered yet.
  2. So that elements with similar properties are grouped togther.