Question

Pick one option:

The ________ ion has a noble gas electron configuration.
Li2+
Li2-
Li
Li+
Li-

Answer 1

The Li+ ion has a noble gas electron configuration, which mirrors the electron configuration of helium (He) by having two electrons in the 1s subshell after losing one valence electron.

Step-by-step explanation:

The Li+ ion has a noble gas electron configuration. Lithium (Li) has an atomic number of 3, which corresponds to three electrons in a neutral atom. These three electrons are arranged in the 1s subshell (two electrons) and the 2s subshell (one electron), giving lithium an electron configuration of 1s²2s¹. When lithium loses its one valence electron, it forms a Li+ cation with a configuration of 1s², which mirrors the electron configuration of the noble gas helium (He). Since lithium is an alkali metal in Group 1A of the periodic table, it tends to form a 1+ charge when it becomes an ion, which is indicated by the noble gas electron configuration it achieves as Li+.

Answer 2

Li⁺

Step-by-step explanation:

Li⁺ ions has a noble gas electron configuration because it resembles that of He.

To have a noble configuration, electrons in the outermost shell must completely fill their respective orbitals.

Li⁺ is an ion that has lost one electron from the usual number of 3 thereby remaining 2 electrons.

The electronic configuration is given as;

Li⁺ 1s²

The S orbital can hold a maximum number of just two electrons.

Helium atom has two electrons with electronic configuration of 1s²

Therefore Li⁺ = 1s² = He