periodicity : ionisation energies and atomic radii

Question 1

what are the factors that affect ionisation energy ?`

Answer 1

nuclear charge
distance from the nucleus
electron shielding

Question 2

what happens to ionisation as you go across a period ?

Answer 2

shows a general increase across a period

Question 3

why does the shielding stay the same across a period ?

Answer 3

• the number of protons increases so there is more attraction acting on the electrons
• electrons are added to the same shell , so the outer shell is drawn inwards slightly
• there is the same number of inner shells –> so shielding will hardly change

Question 4

why does it increase in ionisation energy across a period ?

Answer 4

• as the attraction between nuclear and outer shell increases
• so more energy needed to remove an electron
• this means that the 1st ionisation energy increases across a period

Question 5

what happens to atomic radius across a period ?

Answer 5

• decreases as the increased nuclear charge pulls the electron in towards it

Question 6

what happens at the end of one period and the start of the next period ?

Answer 6

decrease in ionisation energy between them

Question 7

why does this happen to the EOOP and the SOTNP ?

Answer 7

• due to the addition of a new shell , further from the nucleus
  –> increased distance of the outermost shell from the nucleus ; and
  –> increased electron shielding of the outermost shell by inner shells