Chemical Properties-

• All group 7 elements have seven electrons in their outer shell
• This characteristic gives the halogens similar chemical properties
• Halogens react with metals to produce salts
• The word 'halogen' means 'salt former'
• Example reaction: Sodium + chlorine → sodium chloride

  • 2Na(s) + Cl2(g) → 2NaCl(s)
• When sodium and chlorine react, they produce an orange flame and clouds of white sodium chloride
• Reactivity of halogens decreases going down group 7
• When halogens react with iron wool:

  • The table describes the observations
• Halogens react with hydrogen to produce compounds called hydrogen halides
• Example: chlorine reacts with hydrogen to produce hydrogen chloride
• Chemical equation: H2(g) + Cl2(g) → 2HCl(g)
• Hydrogen halides are gases at room temperature
• Hydrogen halides dissolve in water to produce acidic solutions
• Hydrogen chloride dissolves in water to produce hydrochloric acid, HCl(aq)