PERIODIC VARIATION

Atomic Radius is the one-half the distance between the two nuclei in two adjacent

metal atoms or in diatomic molecules

Trend: Left to right: Decreases Top to bottom: Increases

Arrange the following atoms in order of increasing atomic

radius: a. Po, Pb, Rnb. C, Li, Bec. Sr,Mg, Ba

d. P,Si, N

Answersa. Rn, Po, Pbb. C, Be, Lic. Mg, Sr, Bad. N, P, Si

Ionization EnergyThe amount of energy required to remove an electron from atom.Trend: Left to right

increases Top to bottom decreases

Which atom should have a smaller first ionization

energy?A. Oxygen or sulfur

B. Sb or PC. Al or Na

D. Mg or CaE. F or B

Answers:A. Sulfur

B. SbC. NaD. CaE. B

ElectronegativityThe tendency for an atom to

attract electrons towards the positive nucleus.Trend: Left to right

increases Top to bottom decreases

Arrange the following atoms according to increasing

electronegativity.A. I, Br, F, Cl

B. Sr, Sb, Sn, InC. S, F, O

AnswersA. I. Br, Cl, F

B. Sr, In, Sn, SbC. S, O, F

Electron AffinityThe energy released when an electron is added to a gaseous atom to form a

negative ion.

Trend: Left to right increases

Top to bottom decreases

•

Specify which of the following elements you

would expect to have the greatest electron affinity

and which would have the least: K, Co, Si, Cl

Cl, K