Determine what ions are present in the following compounds.
Cr2O3
PbCl4
Na3PO4
Al(ClO4)3
SrSO4
The correct answer and explanation is :
Let’s determine the ions present in the compounds:
- Cr₂O₃ (Chromium(III) oxide)
- Chromium oxide is composed of chromium (Cr) and oxygen (O). The compound Cr₂O₃ indicates that each chromium ion has a +3 charge and each oxygen ion has a -2 charge.
- The two chromium ions (Cr³⁺) balance out the three oxygen ions (O²⁻) to form a neutral compound.
Ions present: Cr³⁺ and O²⁻.
- PbCl₄ (Lead(IV) chloride)
- This compound contains lead (Pb) and chlorine (Cl). In PbCl₄, lead is in the +4 oxidation state (Pb⁴⁺), and chlorine is in the -1 oxidation state (Cl⁻).
- There are four chloride ions to balance the +4 charge of the lead ion.
Ions present: Pb⁴⁺ and Cl⁻.
- Na₃PO₄ (Sodium phosphate)
- Sodium phosphate is composed of sodium (Na), phosphorus (P), and oxygen (O). Sodium (Na) has a +1 charge, phosphate (PO₄) has a -3 charge.
- The three sodium ions (Na⁺) balance the negative charge of the phosphate ion (PO₄³⁻).
Ions present: Na⁺ and PO₄³⁻.
- Al(ClO₄)₃ (Aluminum perchlorate)
- This compound contains aluminum (Al) and perchlorate (ClO₄). Aluminum (Al) has a +3 charge, while perchlorate (ClO₄) has a -1 charge.
- Three perchlorate ions balance the +3 charge of the aluminum ion.
Ions present: Al³⁺ and ClO₄⁻.
- SrSO₄ (Strontium sulfate)
- Strontium sulfate contains strontium (Sr) and sulfate (SO₄). Strontium (Sr) has a +2 charge, and sulfate (SO₄) has a -2 charge.
- The +2 charge of the strontium ion balances the -2 charge of the sulfate ion, forming a neutral compound.
Ions present: Sr²⁺ and SO₄²⁻.
Explanation:
The ions in each compound arise from the different oxidation states of the metals and non-metals involved, based on their positions in the periodic table. Metals such as sodium (Na), strontium (Sr), and aluminum (Al) form positive ions by losing electrons, while nonmetals such as oxygen, chlorine, and phosphate form negative ions by gaining electrons. In each compound, the total positive charge balances the total negative charge, resulting in a neutral compound.