Compare the stability of a lithium atom with that of its ion, li+.

Lithium ion (Li⁺) is more stable than lithium atom (Li) because it has a complete outershell electronic configuration.

Explanation:

To compare the stability of Li atom and its ion Li⁺, we must throw the light on the electronic configuration.Li atom has 3.0 electrons and its electronic configuration is: 1s² 2s¹, the outershell (2s) is half-filled that it contains 1.0 electron.Li⁺ has 2.0 electrons and its electronic configuration is: 1s²,  the outershell (1s) is completely-filled that it contains 2.0 electron and is like the electronic configuration of the noble element (He) which is highly stable.Thus, the lithium ion (Li⁺) is highly stable than lithium atom (Li) because it has a complete outershell electronic configuration.