Question

Which of the following is true for the given
assertion (A) and reason (R):
A: 02-has a smaller ionic size than F-
R: F is followed by O in period 2.​

Answer 1

Answer:

Here all these species are isoelectronic species.

The species which has maximum negative charge will have maximum ionic radii and the species which have maximum positive charge will have minimum ionic radii.

Thus, the order of ionic radii will be:

O

2−

>F

−

>Ne>Na

+

>Mg

2+

Here Ne has greater ionic radii than sodium and magnesium ion as Ne has a van der Waals radius which is larger than the ionic radii of these cations.

Thus radii of Ne should be between F

−

and Na

+

.

i.e. radii of Ne should be greater than 0.95

A

˚

and less than 1.34

A

˚

.

Thus ionic radii of Ne should be 1.12A

0

.

Hence, the correct option is B