Determine the chemical formula for the ionic compound forms between strontium and nitrogen.
The correct answer and explanation is :
The chemical formula for the ionic compound formed between strontium (Sr) and nitrogen (N) is Sr₃N₂.
Explanation:
To understand how this formula is determined, it’s essential to first consider the valence charges of the ions involved and how they combine to form a neutral ionic compound.
- Strontium (Sr):
- Strontium is an alkaline earth metal located in Group 2 of the periodic table. Elements in Group 2 have two valence electrons.
- When strontium forms an ionic compound, it loses these two electrons to achieve a stable electron configuration, similar to the nearest noble gas (krypton, in this case).
- This results in a 2+ charge on the strontium ion: Sr²⁺.
- Nitrogen (N):
- Nitrogen is a non-metal located in Group 15 of the periodic table. It has five valence electrons and needs three more electrons to complete its octet and achieve a stable electron configuration (similar to neon).
- To obtain this octet, nitrogen gains three electrons, which gives it a 3- charge: N³⁻.
- Forming the Ionic Compound:
- The ionic compound must be neutral overall. This means the total positive charge from the cations (strontium ions) must balance out the total negative charge from the anions (nitride ions).
- Strontium has a +2 charge, and nitrogen has a -3 charge. To balance the charges, we need:
- 3 strontium ions (each with a +2 charge) to give a total charge of +6.
- 2 nitrogen ions (each with a -3 charge) to give a total charge of -6.
- The total positive charge (+6) balances with the total negative charge (-6), resulting in a neutral compound.
- Chemical Formula:
- The ratio of strontium ions to nitride ions is 3:2, leading to the chemical formula Sr₃N₂ for the ionic compound formed between strontium and nitrogen.
Thus, the chemical formula for the ionic compound between strontium and nitrogen is Sr₃N₂, which ensures charge neutrality.