Periodic Table Groups Mind Map

1. React with oxygen to form oxides

   Nota:

   • \[4Li + 0_2 -> 2li_20\]
   1. Shiny when freshly cut but tarnish rapidly in moist air
2. React with water to form hydroxides and hydrogen gas
   1. Alkali metal + water -> Metal hydroxide + Hydrogen gas

      Nota:

      •  \[2Li + 2 H_2O -> 2LiOH + H_2\]
3. React with chlorine and bromine to form chlorides and bromides

   Nota:

   • \[2Li+Cl_2->2LiCl\]
   1. colourless, crystal salts
4. Become more reactive as the group is descended
   1. Why?
      1. Octet rule: When placing electrons in orbits, the electron configuration with a full outer shell is preferable
         1. In a reaction with a non-metal, an alkali metal loses the single electrons in its outermost shell
            1. Moving down the group, the atom gets bigger and electrons feel less attraction from the nucleus
               1. Giving away the outermost electron becomes easier and hence the elements become more reactive
5. Low melting point
6. Soft
7. Easily cut

1. Lithium
   1. Crimson red
2. Sodium
   1. Orange
3. Potassium
   1. Lilac

1. All exist as diatomic molecules
2. Density, boiling point and melting point increase moving down the group
3. React with metals to form salts

   Nota:

   •  \[Cl_2 +Mg -> MgCl_2\] \[F_2 + 2Na -> 2NaF\]
   1. These salts have many uses
      1. NaCl - Table salt
      2. NaBr - Disinfectant for pools
4. Can be used as disinfectants and bleaches as they kill microorganisms and remove colour
5. React with hydrogen to form hydrogen halides

   Nota:

   • \[H_2 + Cl_2 -> 2HCl\]
   1. When these halides dissolve in water, they break up into a positive and negative ion
6. Reactivity decreases down the group
   1. A more reactive halogenw ill displace a less reactive halogen in a displacement reaction
   2. According to the octet rule, halogens gain one electron when they react
      1. Moving down the group, atoms become bigger and electrons feel less attraction from the nucleus
         1. Gaining an electron becomes less favourable and hence elements become less reactive

Nota:

• \[Ag^{+}(aq)+Cl^{-}(aq)-> AgCl(s)\]

1. Chloride
   1. White
2. Bromide
   1. Pale yellow
3. Iodide
   1. Yellow

1. Colourless
2. Low melting and boiling points points
3. Poor conductors of heat and electricity
4. Inert: They do not react easily
   1. Octet rule is already satisfied since they have a full outer shell
5. Exist as single atoms

1. Helium : Weather balloons
   1. Low density and non-flammable
2. Neon: long lasting illuminated signs
   1. Produces a distinctive red-orange light when electricity is passed through it