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.

b. +3 and +6.

Explanation:

Zeff = Z - S

The Z denotes the no of protons i.e. atomic number

S denotes the non-valence electrons

For boron,

the electronic configuration is 1s₂ 2s₂ 2p₄

Now  

Z = 5, S = 2

So,  

Zeff = 5-2

= +3

For O, the electronic configuration is 1s₂ 2s₂ 2p₄

So,  

Z = 8, S = 2

= 8-2

= +6

Hence, the second option is correct

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