Answer:
+3
12 electrons and 15 protons.
Explanation:
The element having 15 electrons and 15 protons have atomic number 15. We know that when an atom lose or gain the electron ions are formed.
Anion formation:
Anion is formed when electron is accept by an atom.
X + e⁻ → X⁻
Cation formation:
Cation is formed when electron lose be an atom.
X → X⁺ + e⁻
The given atom loses 3 electrons thus oxidation number will be +3 and cation is formed.
X → X³⁺ + 3e⁻
Now element X have 15 protons and 12 electrons.
