Question

How do you write the ion notation for an atom with 20 protons and 18 electrons?

Answer 1

`Ca^(2+)`

Explanation:

If it has got 20 protons, 20 positively charged, massive nuclear particles, the element is calcium by defintion, i.e. `Z`, the atomic number `=` `20`.

The neutral metal has 20 electrons; the metal can ionize to form caclium ion, `Ca^(2+)`.