Question

An element ‘M’ has 25% of the electrons filled in the third shell as in the second shell. The element ‘M’ is ______.

Options

• Sodium

• Magnesium

• Aluminium

• Calcium

Answer 1

An element ‘M’ has 25% of the electrons filled in the third shell as in the second shell. The element ‘M’ is magnesium.

Explanation:

Magnesium’s second shell contains eight electrons, whereas its third shell contains two electrons in 25% of cases. The electrical configuration of magnesium is 2, 8, 2.