Identify the correct statements from the following :

A. Heisenberg uncertainty principle is applicable to electrons.

B. The size of $2 p_x$ orbital is less than the size of $3 p_x$ orbital.

C. The energy of 2 s orbital of H atom is equal to the energy of 2 s orbital of Li .

D. The electronic configuration of Cr is $[\mathrm{Ar}] 3 \mathrm{~d}^5 4 \mathrm{~s}^1$

Choose the correct answer from the options given below:

The species having identical radii according to the Bohr's theory are :

A. H (first orbit)

B. $\mathrm{He}^{+}$(first orbit)

C. $\mathrm{He}^{+}$(Second orbit)

D. $\mathrm{Li}^{2+}$ (first orbit)

E. $\mathrm{Be}^{3+}$ (Second orbit)

Choose the correct answer from the options given below :

What is the ratio of wave number of first line (lowest energy line) of Balmer series of H atomic spectrum to first line of its Brackett series?

Which of the following is correct set of 4 quantum numbers of $19^{\text {th }}$ electron in Chromium (Atomic number $=24$ ) in accordance with Aufbau principle?