Question

Which one of the following has the largest atomic radius
Sodium
Magnesium
Aluminium
Potassium

Answer 1

potassium has the largest atomic radius as its atomic no. is 19 and whereas comoare to other elements more shells are required for the filling of electrons so greater ionic radii

Answer 2

Answer: The correct answer is potassium.

Explanation:

Atomic radius of an atom is defined as the distance from the nucleus to the outermost orbital of electron.

This factor decreases as we move from left to right in a period because electrons gets added up in the same sub-shell and its attraction towards the nucleus increases, which in turn decreases the size.

This factor also increases as we move from top to bottom in a group because there is an addition of shell around the nucleus and the outermost orbital gets far away from the nucleus and hence, the distance between the nucleus and outermost orbital increases.

For the given elements:

Sodium belongs to Period 3 and Group 1.

Magnesium belongs to Period 3 and Group 2.

Aluminium belongs to Period 3 and Group 13.

Potassium belongs to Period 4 and Group 1.

Thus, potassium has the largest atomic radii.