Question

The shielding of electrons gives rise to an effective nuclear charge, Z_eff which explains why boron is larger than oxygen. Estimate the approximate Z_eff felt by 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

Answer 1

Concepts and reason

Effective Nuclear Charge

The effective nuclear charge is defined as the net attractive interaction between the positive charge of nuclear protons and the negative charge of valence electrons. It is always less than the actual nuclear charge of the atoms.

Shielding Effect

The shielding effect is the diminishing of attractive interaction between the nuclear protons and the valence electrons by inner electrons.

Fundamentals

Mathematical equation for the effective nuclear charge:

$Zer=Z-S $

Where,

The atomic number of the atom is Z.

The nonvalenced electrons or core electrons is S.

The atomic symbol for boron atom is.

The atomic number of boron is 5. (Z=5)

The ground state electronic configuration of boron atom is

The nonvalence electrons or core electrons of boron are 2. (S=2)

The valence electrons of boron atom are 3.

The atomic symbol for oxygen atom is.

The atomic number of oxygen is 8. (Z=8)

The ground state electronic configuration of oxygen atom is

The nonvalence electrons or core electrons of oxygen are 2. (S=2)

The valence electrons of oxygen atom are 6.

Ans:

The approximate felt by a valence electron of boron and oxygen atoms are +3 and +6, respectively.