topic 03 - group 7, the Halogens

• what are the group 7 elements known as?

  the Halogens
• what does Halogens mean?

  salt formers
• why are group 7 called the halogens?

  became they react with the groups 1 2 and 3 to form ionic compounds or salts.
• what re all ionic compounds?

  salts
• how do the halogens exist naturally?

  as diatomic molecules where 2 of the same halogen atoms are covalently bonded to each other.
• what is the formula of fluorine?

  F2
• what is fluorine's physical appearance at room temp?


  pale yellow gas
• what is the formula of chlorine?

  Cl2
• what is chlorine's physical appearance at room temp?


  pale green gas
• what is the formula of bromine?

  Br2
• what is bromine's physical appearance at room temp?


  dark red/brown liquid
• what is the formula of iodine?

  I2
• what is iodine's physical appearance at room temp?

  dark grey solid
• what does boiling point reveal?

  the temp at which a substance changes state from liquid to gas, it can be used as a measure of the amount of energy needed to overcome any forces of attraction between the particles to move them away from each otjher
• what happens when halogens change their physic state?

  the molecules move further apart, for this movement to occur, the forces of attraction between the molecules must be overcome.
• what type of intermolecular forces occurs between the halogen molecules?

  • van der Waals
  • the weakest intermolecular force
• how does boiling points change going down group 7?

  bp increases descending group 7
• why does boiling points increase going down group 7?

  • bp is influenced by the strength of intermolecular force
  • the stronger the intermolecular forces, the higher the amount of energy needed to overcome them and the higher the bp will be
  • as we go down group 7, the diatomic molecules get larger so the strength of the intermolecular forces acting between them increases.
• what is electronegativity?


  an atom's ability to attract the electron pair in a covalent bond
• how is electronegativity influenced by the force of attraction in a molecule?

  • the more shells between the nucleus and the electrons being shared. the higher the shielding effect and the less easily the atom can withdraw the electrons towards itself
• why don't group 0 have electronegativity values?


  they tend to exist as single atoms so don't tend to form covalent bodns
• how does electronegative change as you go left to right across the periodic table?

  electronegativity values increases going left to right.