The shielding of electrons gives rise to an effective nuclear charge, Zeff, which explains why boron is larger than oxygen. Estimate the approximate Zeff felt by a valence electron of boron and oxygen, respectively.
a. +5 and +8.
b. +3 and +6.
c. +5 and +6.
d. +3 and +8.
e. +1 and +4.