periodic trends

• Periodic Trends


  Trends in atomic radii and ionic radii across periods and down groups, including Groups 1, 2, 13-18 and Period 3
• Across a period, the trend is that the oxides of elements become less alkaline and more acidic. In the middle of the group (e.g. Al) we see amphoteric oxides, which can act as an acid or alkali in different circumstances.
• Ionic radii


  1. Electrons shown

  2. Gain one electron to have full shell

  3. Cations get smaller

  4. Anions get larger
• Cations


  Easier to lose one electron than gain another seven
• Cations


  Decrease in size
• Anions


  Increase in size
• The blue represents what the ions become
• All the anions get a massive increase in size
• All the cations get a decrease in size
• The pink ones all get smaller
• The ionic trend is that they get gradually smaller and then jump up to a large size
• There should be a slight decrease because of the nuclear charge
• The atomic radii effects are very similar but you need to take into account the massive decrease for the cations and massive increase for the anions