Explain the trend in ionisation energy down group 2? (3)

• down group 2 the number of protons increases therefore the nuclear charge increases (protons are found in the nucelus and have a +1 charge)

• the number of shielding electrons increases (each member down has an extra shelf of electrons)

• the number of electrons in the outer shelf remains the same (all have 2)

• the force of attraction between the outer electrons and the nucleus decreases, (due to shiedling) therefore ionisation energy decreases (less energy required to remove the outer electron due to weaker electrostatic attraction between the nucleus and outer electrons)