Test Index

WAEC Chemistry 2017 Paper

Question : 4

Total: 50

The species with no electron in the 3d-orbital is

Solution:

Concept:

A species has no electron in the

3d

-orbital when its electronic configuration shows that all

3d

orbitals are empty.

Explanation:

Write the outer electronic configurations and remove electrons according to the charge.

Scandium has

1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{1}4s^{2}

For

Sc^{3+}

, remove three electrons: first from

4s

, then from

3d

So,

Sc^{3+}

becomes

1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}

Thus,

Sc^{3+}

has completely empty

3d

-orbitals.

Answer:

Sc^{3+}

— Option B.

Go to Question:

Prev Question

Next Question