C2 - Additional Chemistry(Higher Tier) - Atomic Structure, Reactions and Rates

Isotopes:

• Are atoms of the same element, with the same number of protons but a different number of neutrons in the nucleus of an atom.

M.r - Relative Molecular Mass:

• Total atomic masses present in a substance/molecule combined.

A.r - Relative Atomic Mass:

• Mass of a single atom.

Reactions between Alkali Metals and Water:

Example: Sodium + Water ====> Sodium Hydroxide + Hydrogen

Why does the reactivity change as you descend through Group 1(Alkali-Metals)?:

• Each alkali-metal has one ELECTRON in it's outermost shell. They want to LOSE this electron, to allow the other electron shell's to be completed. As you descend through Group 1 of the Periodic Table, it becomes easier on the subsequent alkali-metal to lose that outer-shell electron due to the distance of that outer shell electron from the NUCLEUS of the atom.(Electron distance from the Nucleus increases = More violent reaction)

Reactions with the Halogens:

• Metal + Halogen =====> Metal Halogen

Alkali Metal + Halogen ====> Alkali Metal Halogen Salt

Why does the reactivity of the Halogens increase as you ascend through group 7?:

Each HALOGEN wants to GAIN an EXTRA ELECTRON to fill it's outermost shell, to give a full outer-shell of ELECTRONS. As you ascend through Group 7 of the Periodic table, it…