Group 7 - Halogens

• Describe Fluorine

  A poisonous yellow gas and is very reactive
• Describe Chlorine

  A poisonous green gas and is less reactive than fluorine
• Describe Bromine

  A ready brown volatile liquid and poisonous
• Iodine

  Dark grey solid that can form poisonous purple vapours, however also an antiseptic which has saved millions of lives
• What does the term 'Diatomic Molecules' mean

  When all of the halogens can exist in pairs of atoms
• How do the atoms become diatomic molecules?

  By sharing electrons and forming a covalent bond
• What do we mean by the term 'Simple molecular structures'

  When halogens can form covalent bonds with other non-metals; such as hydrogen or carbon to form compounds such as hydrogen fluoride or carbon tetrachloride
• As you go down group 7, what trend can we see that is the opposite of Group 1 elements?

  The melting and boiling points increase + reactivity decreases due to the outermost shell getting further away from the positive nucleus so the attractive force needed to pull in an extra electron from another atom gets weaker. If the halogen can't attract an electron to complete its outer shell, then it cannot react
• Define the term 'Halide'

  When a halogen gains an electron to form a 1- ion, we call it a 'Halide'