Which ions are present in SrSO4?
The correct answer and explanation is:
Correct Answer: The ions present in SrSO₄ (strontium sulfate) are:
- Strontium ion (Sr²⁺)
- Sulfate ion (SO₄²⁻)
Explanation:
SrSO₄ is an ionic compound formed by the combination of a metal (strontium) and a polyatomic ion (sulfate). Ionic compounds consist of positively charged ions called cations and negatively charged ions called anions held together by electrostatic forces.
Strontium is a group 2 alkaline earth metal with atomic number 38. In chemical reactions, strontium tends to lose its two outermost electrons to achieve a stable electron configuration. By losing two electrons, a strontium atom forms a Sr²⁺ ion. This ion has a positive charge because it now has two more protons than electrons.
Sulfate is a polyatomic ion with the formula SO₄²⁻. It is made of one sulfur atom covalently bonded to four oxygen atoms. The sulfate ion carries a -2 charge overall. This charge arises from the extra electrons that are not balanced by protons, making the ion negatively charged.
In SrSO₄, the Sr²⁺ and SO₄²⁻ ions combine in a 1:1 ratio to form a neutral compound. The charges cancel each other out: +2 from Sr²⁺ and -2 from SO₄²⁻.
This ionic compound is sparingly soluble in water. That means only a small amount of it dissolves in water, dissociating into its ions. In aqueous solution, the dissolved portion of SrSO₄ breaks apart into free Sr²⁺ and SO₄²⁻ ions. However, most of the solid remains undissolved due to its low solubility product (Ksp).
Understanding the ions in SrSO₄ is essential in fields like chemistry and environmental science because strontium compounds are found in minerals and are used in medical imaging and fireworks.