Which of the following compounds exhibits both ionic and covalent bonding?
A) Cl2O2 B) KCI C) KNO, D) N,O4
The Correct Answer and Explanation is:
The correct answer is C) KNO₃ (potassium nitrate).
Explanation:
To understand why KNO₃ exhibits both ionic and covalent bonding, let’s break down its structure and bonding types.
1. Understanding Ionic and Covalent Bonds
- Ionic Bonds occur between a metal and a nonmetal, where electrons are transferred from one atom to another. This typically results in positively and negatively charged ions that attract each other due to electrostatic forces. For example, potassium chloride (KCl) forms an ionic bond between potassium (K) and chlorine (Cl).
- Covalent Bonds occur between two nonmetals and involve the sharing of electron pairs between atoms. This type of bonding creates a molecule rather than an ionic compound.
2. Structure of KNO₃
Potassium nitrate, KNO₃, consists of:
- Potassium Ion (K⁺): Potassium (K) is a metal that readily loses one electron to form a K⁺ ion, achieving a stable electron configuration.
- Nitrate Ion (NO₃⁻): The nitrate ion (NO₃⁻) is a polyatomic ion, meaning it contains more than one atom bonded together. The atoms within NO₃⁻ are held together by covalent bonds, where nitrogen and oxygen atoms share electrons to achieve stability.
3. Bond Types in KNO₃
- The bond between potassium (K⁺) and the nitrate ion (NO₃⁻) is ionic because it involves the electrostatic attraction between a positively charged K⁺ ion and a negatively charged NO₃⁻ ion.
- Within the nitrate ion (NO₃⁻), nitrogen and oxygen atoms are bonded covalently. Nitrogen shares electrons with oxygen atoms, forming covalent bonds and resulting in a stable polyatomic ion.
4. Why KNO₃ Exhibits Both Bond Types
The presence of both ionic and covalent bonds in KNO₃ is due to its composition of a metal ion (K⁺) and a polyatomic ion (NO₃⁻). While the potassium ion interacts ionically with the nitrate ion, the nitrogen and oxygen atoms within the nitrate ion are covalently bonded.
In summary, KNO₃ (potassium nitrate) exhibits both ionic and covalent bonding because it consists of an ionic bond between potassium and nitrate and covalent bonds within the nitrate ion itself. This makes KNO₃ a compound with mixed bonding types, which is common in many salts containing polyatomic ions.