Here's why:
* Group 1 Elements: Alkali metals have one valence electron.
* Oxygen: Oxygen needs two electrons to achieve a stable octet configuration.
* Ionic Bonding: Alkali metals readily lose their single valence electron to form a +1 cation (X⁺). Oxygen gains two electrons to form a -2 anion (O⁻²).
* Neutral Compound: To create a neutral compound, you need two X⁺ cations to balance out the -2 charge of the O⁻² anion, resulting in the formula X₂O.
Example: Sodium (Na) is a Group 1 element. Its oxide is Na₂O (sodium oxide).
