Which of the following is true ?

Options

A. The outer electronic configuration of the ground state chromium atom is `3d^4 4 s^2`.
B. Gamma rays are electromagnetic radiations of wavelength of `10^-6 cm` to `10^-5 cm`.
C. The energy of the electron in the `3d` orbital is less than that in the `4s` orbital of a hydrogen atom.
D. The electron density in the `xy-"plane"` in `3 d_(x^2 - y^2)` orbital is zero.

Answer

C

Explanation

( c) (a) False. The configuration is `3 d^5 4 s^1`.
(b) False. The wavelength of gamma rays is of the order of `10-11 m`.
( c) True. In hydrogen atom, the energy of an electron depends only on the principal quantum number of the orbital which it occupies.
(d) False. In xz-plane, there is no electron density if an electron occupies `3 d_(x^2 - y^2)` orbital.