Question

Which of the following electron configurations has maximum energy ?

A.

B.

C.

D.

Answer 1

Energy of orbitals and shell: 1s is the least energy orbital and it is close to the nucleus. 1s is first then second shell, which consists of $2s$ and $2p$. The second shell has high energy and is away from the nucleus than the first shell.

Complete step by step solution:
The order of increasing energy of the sub-atomic orbitals is $s < p < d < f$.
The energy in an excited state is more than that in the ground state.

So, the correct answer is A.

Additional information:
Each orbital in an atom is considered by a unique set of values of the three quantum numbers $n,l$ and $m$, which resemble the electron's energy, angular momentum, and angular momentum vector components . Each orbital can be engaged by a maximum of two electrons, each with its own spin quantum number. The simple names $s$ orbital, $p$ orbital, $d$ orbital, and $f$ orbital refer to orbitals with angular momentum quantum numbers having $l = 0,1,2,3$ respectively. The names together along the value of n are used to describe the electron configurations of atoms. These are derived from the description by early spectroscopists of certain series of alkali metal .Orbitals for $l > 3$ continue alphabetically.

Note: Atomic orbitals are known as the basic building blocks of the atomic orbital model which is also known as the electron cloud or wave mechanics model. It is a modern framework for visualizing the smallest behavior of electrons. In this model the electron cloud of a multi-electron atom is seen as being built up in an electron configuration which is a product of simpler hydrogen-like atomic orbitals.