Question

what is the symbol for the ion that forms when oxygen gains two electrons? o+2e−→ o²+ o²− o₂−

Explanation:

When an atom gains electrons, it forms a negatively - charged ion (anion). Oxygen has 8 protons (atomic number = 8). In a neutral oxygen atom, the number of electrons is also 8. When it gains 2 electrons, the number of electrons becomes \(8 + 2=10\). The charge on an ion is calculated as \( \text{Charge}=\text{Number of protons}-\text{Number of electrons}\). So, the charge \(=8 - 10=- 2\). The symbol for an oxygen atom is \(O\), and for an ion, the charge is written as a superscript.

Answer:

\(O^{2 -}\)