Topic 6 - Groups in The Periodic Table

Elements in group 1

alkali metals

elements in group 7

halogens

elements in group 0

noble gases

alkali metals properties

similar to other metals, except soft with low melting points. react with water to form metal hydroxide and hydrogen. reactivity increases as you go down the group

why does reactivity increase as you go down the alkali metals group

there are more shells, and these shells shield the outer electron, reducing its attraction to the nucleus

state of halogens at room temperature

chlorine - yellow green gas

bromine - red brown liquid

iodine - dark grey solid

properties of halogens

as you go down the group, melting points and boiling points increase. halogens and metals react to produce metal halides. hydrogen and halogens react to produce hydrogen halides

test for chlorine

substance bleaches damp blue litmus paper red

why do halogens become less reactive down the group

the shells are shielded, so the forces of attraction (to gain an electrron) are weaker

noble gases properties

inert because full outer shells. helium has low density, argon prevents metals burning.

trends as you go down the group (noble gases)

the densities and the boiling points increase