Calcium, a metal with 20 electrons, tends to lose two, forming a 2+ cation that has the same number of electrons as ________.
A) Helium
B) Neon
C) Argon
D) Krypton
E) Xenon

Question

Quizplus · Accepted Answer

Calcium has 20 electrons in its neutral state, but tends to lose two electrons to form a 2+ cation. When it does this, it now has the same electron configuration as the noble gas Argon (which has 18 electrons), making it stable.

Calcium, a Metal with 20 Electrons, Tends to Lose Two