For an atom A, the ground state electronic configuration is given as $(1 s)^{2} (2 s 2 p)^{8} (3 s 3 p)^{8} (3 d)^{10} (4 s 4 p)^{x}$ .
If the effective nuclear charge ( $Z_{e ff}$ ) experienced by a valence electron is $6.95$

find the value of $x$ .

Question

For an atom A, the ground state electronic configuration is given as $(1 s)^{2} (2 s 2 p)^{8} (3 s 3 p)^{8} (3 d)^{10} (4 s 4 p)^{x}$ .

If the effective nuclear charge ( $Z_{e ff}$ ) experienced by a valence electron is $6.95$

find the value of $x$ .

TestHub · Accepted Answer

Valence shell

The outermost shell is n = 4, which contains 4s and 4p orbitals.

So valence electrons are in 4s4p.

Number of valence electrons using Zeff

Zeff (effective nuclear charge) ≈ actual nuclear charge seen by valence electron after shielding.

Given Zeff = 6.95 → almost 7 → implies 6 electrons in outermost shell (4th shell).

Assign electrons in orbitals

4th shell orbitals: 4s can hold 2, 4p can hold 6.

Total electrons = 6 → configuration = 4s² 4p⁴

x = 6

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