Question

A lithium atom in the excited state contains the same number of electrons as a lithium atom in the ground state. However, in the excited state one or more of the electrons are temporarily located in a higher energy level. Which of the following is the electron configuration for a Li atom in its excited state?

1s23s1


1s22s2


1s2



1s22s1

Answer 1

Answer:1s22s1

Step-by-step explanation:

Answer 2

Answer: 1s2 3s1

Explanation:

Lithium is element number 3 so it has 3 electrons. In the ground state, 2 electrons are in the 1s shell and 1 electron is in the 2s shell.

1s23s1 Correct answer. 2 electrons are still in the 1s shell, but the third electron has jumped to the 3s shell.

1s22s2 Wrong: This atom has gained an additional electron in the 2s shell

1s2 Wrong: This atom has lost an electron.

1s22s1 Wrong: This atom is in its ground state.