Alkali metals and halogens

• 1. Lithium reacts with oxygen to form lithium oxide, Li2O.
• Sodium reacts vigorously with chlorine gas to produce sodium chloride (table salt) and hydrogen chloride gas.
• Potassium reacts violently with water to produce potassium hydroxide solution and hydrogen gas.
• 1. Sodium reacts with oxygen to form sodium oxide, Na2O or sodium peroxide, Na2O2. 
• 1. Potassium reacts with oxygen to form potassium peroxide, K2O2, or potassium superoxide, KO2.
• Group 1 metals are....

  Lithium (Li)

  Sodium (Na)

  Potassium (K)

  Rubidium

  Caesium

  Francium
• Properties of alkali metals (group 1)

  • Soft metals which can easily be cut with a knife
  • Low densities and melting points
  • Very reactive (only lose one electron to become stable)
• Group 1 metal + water --> metal hydroxide + oxygen
• Halogens elements are...

  Flourine

  Chlorine

  Bromine

  Iodine

  Astatine
• fluorine is a yellow gas at room temperature and is highly reactive
• chlorine is a greenish-yellow gas that is toxic
• Bromine is a red-brown volatile liquid which is also poisonous.
• Iodine is a purple black solid
• the melting and boiling points of halogens increase as you go down the group
• The halogens decrease in reactivity going down the group
• • The halogens react with some metals to form ionic compounds which are metal halide salts
• • The rate of reaction is slower for halogens which are further down the group such as bromine and iodine