Having a 2 charge means the atom gave away 2 of its former electrons. Since it now has 18, it originally had 20 electrons. Recall that atoms have the same number of electrons as protons, and the atomic number of an atom is the number of protons it has. So, the atom in question is the atom whose atomic number is 20..thats calcium (Ca).
This post is last updated on hrtanswers.com at Date : 1st of September – 2022