Gallium is slightly more electronegative than aluminum
CHEMISTRY · Single correct · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Gallium is slightly more electronegative than aluminum, even though it lies below Al in group 13. Which of the following best explains this deviation from the usual down-group trend?
(a) Although Ga has more protons than Al, its many inner electrons completely cancel the additional nuclear charge, lowering electronegativity.
(b) The extra valence shell in Ga places bonding electrons farther from the nucleus, decreasing the effective nuclear charge they experience.
(c) Filled 3d electrons in Ga shield the nuclear charge poorly, so the valence electrons experience a higher effective nuclear charge than in Al.
(d) Because Ga has a more exothermic electron affinity than Al, it therefore pulls more strongly on bonding electrons, making it more electronegative regardless of shielding effects.