The number of correct statements from the following is _______
A. For 1s orbital, the probability density is maximum at the nucleus
B. For 2s orbital, the probability density first increases to maximum and then decreases sharply to zero.
C. Boundary surface diagrams of the orbitals encloses a region of 100% probability of finding the electron.
D. p and d-orbitals have 1 and 2 angular nodes respectively
E. probability density of p-orbital is zero at the nucleus

Analyzing each statement:

A. For 1s orbital, probability density is maximum at the nucleus — True. The radial probability density $$|\psi|^2$$ for 1s is maximum at r = 0.

B. For 2s orbital, probability density first increases then decreases sharply to zero — False. The 2s orbital has a radial node where probability density goes to zero, then increases again.

C. Boundary surface diagrams enclose 100% probability — False. They typically enclose about 90-95% probability.

D. p and d orbitals have 1 and 2 angular nodes respectively — True. Angular nodes = l (l=1 for p, l=2 for d).

E. Probability density of p orbital is zero at the nucleus — True. The p orbital has a node at the nucleus.

Correct statements: A, D, E = 3