Unit 1: Electrons and Periodicity

Question 1

Atomic radius

Answer 1

radius of an atom from nucleus to valence electrons

Question 2

Ionization energy

Answer 2

energy necessary to be added to an atom to remove an electron

Question 3

Electron Affinity

Answer 3

– energy released by an atom in gaining an electron

Question 4

Ionic radius

Answer 4

radius of an ion from nucleus to valence electrons

Question 5

Atomic Radius

Answer 5

Electrons affected by nuclear pull

Effective nuclear charge (Zeff) – the partially screened (shielded) nuclear charge

Shielding effect – decrease in nuclear attraction caused by inner electron repulsion

Ex: Li – outer 1 e- not 3 proton; not 1 proton (2s penetrates 1s somewhat)

Shielding > for higher n value

Allows outer e- to move further

Question 6

Atomic Radius

Answer 6

Can talk trends; not always valid

Down group, higher n so bigger atom

Across period (left à right) same n, more protons

Higher Zeff on same n, closer

Less regular for transition