Question

Which of the following statements is correct?
(A) The greatest probability of finding a $1s$ electron is at the nucleus.
(B) The size of an orbital is directly proportional to its principal quantum number.
(C) A $3p$ orbital can hold three electrons.
(D) A $2s$ orbital is different from a $1s$ orbital because the $2s$ orbital requires more energy for the electrons to fill it.

Answer 1

Orbital is the region where there is a maximum probability of finding an electron. At the nucleus, there will be no electrons. The size of an orbital is directly proportional to the square of the principal quantum number. Each orbital can accommodate two electrons only. The electrons are filled in the orbitals according to the order of the orbitals.

Complete Step By Step Answer:
Nucleus consists of only protons and electrons but not electrons. Thus, the given statement a is not correct.
The size of the orbital is directly proportional to ${n^2}$ , where n is the principal quantum number.
A $3p$ orbital can accommodate only two electrons only. As each orbital can accommodate two electrons.
According to the Moeller diagram, the energy of $2s$ is more than the $1s$ . Thus, more energy is required for the electrons to fill the $2s$ orbital.

Note:
Shell consists of sub-shells in which the first shell consists of only one sub-shell, the second shell consists of two sub-shells. Each subshell consists of orbitals and each orbital can accommodate two electrons only. The shell $n = 1$ is the shell consisting of one subshell and the orbital is $1s$ . The definitions of shell, sub-shell, and orbital are nearer but not the same.