Chemistry, ES Revision Notes


The Dead Sea

  • Extremely high water density

    • Salt is 350gdm-1

    • Normal is 40gdm-1

  • 400m below sea level

  • Huge evaporating basin

  • High proportion of bromide salts

  • Major source of minerals

  • Mainly group 7 ions

The p-block, Group 7

  • Halogens are group 7 elements

  • All have 7 electrons in outer shell

  • Most reactive group of non-metals

  • Not found naturally in elemental form

  • Abundance decreases down group

  • All occur as diatomic molecules

Halogen bonding in compounds

In compounds, there several ways by which a halogen can achieve stability:

  • Gaining an electron from a metal atom, forming a halide ion in an ionic compound

  • Sharing an electron with a non-metal atom in a covalently bonded compound

Physical Properties of Halogens

A table to show the physical properties of some halogens