The Periodic Table: Periodicity Key Terms and Definitions

Question 1

First Ionisation Energy

Answer 1

The energy required to remove one electron from each atom in one mole of gaseous atoms

Question 2

The magnitude of an ionization energy is influenced by…?

3 things

Answer 2

• Nuclear charge; the greater the nuclear charge, the greater the attraction of the outer electrons
• Atomic Radius; the further the electron is from the nucleus, the weaker the attraction
• Shielding; full inner shells of electrons exert a repelling effect on outer electrons, this reduces the attraction between the nucleus and outer electrons

Question 3

Trends in ionisation energy;

Down a group

Answer 3

I.E decreases down a group

• nuclear charge increases
• atomic radius increases so the outer electron is further from the nucleus
• shielding increases as the number of full inner shells increases
• increase in distance and shielding outweigh the increased nuclear charge
• the nuclear attraction on the outer electron decreases