Answer:
C. He
Explanation:
When lithium is ionized, its new electronic configuration is the same as that of a helium atom.
Lithium is made up of 3 electrons with a configuration of:
2, 1
it has 1 electron in its outermost shell.
As a metal lithium will prefer to lose an electron due to its electropositivity.
On losing an electron, it will have 2 electrons remaining
Now, Helium has 2 electrons and this makes it similar to Lithium that has lost one electron.
This makes Lithium isoelectronic with Helium.
