Question

What is the only element that can form both a cation and an anion?

Answer 1

Hydrogen?

Explanation:

You are probably referring to hydrogen, which can form `1^+` and `1^-` ions.

However, there are other elements that can form both cations and anions, such as arsenic, which can form `3^-`, `3^+`, and `5^+` ions; and tellurium, which can form `2^-` and `4^+` ions.