Question

Three concentric conducting spherical shells carry charges +4Q on the inner shell , -2Q on the middle shell and +6Q on the outer shell . The charge on the inner surface of outer shell is

Answer 1

Down a group

As the electron enters a new shell, the distance between the nucleus and the outermost electron increases. Thus, atomic size increases down a group.

2. Along a period

As there is no new shell appearing along a period, the distance between the nucleus and the outermost electron remains same but due to attraction between the nucleus and the electron, the distance decreases. Thus, the atomic size decreases along a period.

But, an exceptional case is there of noble gases as they have larger atomic size as compared to the elements in that period because of negligible Van der Waals forces of attraction.

Hope it will help