Question

Na, Mg and Al are the elements having one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each.

Answer 1

Answer:

Sodium Na has largest atomic radius.

Aluminum Al is least reactive.

Explanation:

• All the given elements Na, Mg, Al belong to third period. As we move across the period from left to right, the force of attraction between the nucleus and electrons increases. As the electrons entered in same subshell. So the radius decreases. Therefore the Sodium has largest size.
• As we move in period, the nuclear charge increases from left to right. So it becomes difficult to remove the electron from an atom. Therefore Al is least reactive among the given elements.