Select the single best answer.\

Rb

has a lower

IE_(1)

than

Sr

, but

Sr

has a lower

IE_(2)

than

Rb

because:\ The radius of

Rb

is smaller than that of

Sr

.\

IE_(1)

increases from left to right across a period. However, because

Rb

has only one valence electron,

IE_(2)

for

Rb

involves the removal of a core electron - requiring significantly more energy.\ The radius of

Sr

is larger than that of

Rb

.\

IE_(1)

decreases from left to right across a period and

IE_(2)

increases from left to right across a period.\

IE_(1)

increases from left to right across a period and

IE_(2)

decreases from left to right across a period.

Select the single best answer. Rb has a lower IE1 than Sr, but Sr has a lower IE2 than Rb because: The radius of Rb is smaller than that of Sr. IE1 increases from left to right across a period. However, because Rb has only one valence electron, IE2 for Rb involves the removal of a core electron - requiring significantly more energy. The radius of Sr is larger than that of Rb. IE1 decreases from left to right across a period and IE2 increases from left to right across a period. IE1 increases from left to right across a period and IE2 decreases from left to right across a period