Ionic bond is defined as the electrostatic force of attraction holding the oppositely charged ions. Ionic compounds are mostly crystalline solid having high melting and boiling points, electrical conductivity in moleten state, solubility in water etc. Covalent bond is defined as the force which binds atoms of same or different elements by mutual sharing of electrons in a covalent bond. Covalent compounds are solids, liquids or gases. They have low melting and boiling points compounds. They are more soluble in non-polar solvents.
The valence electrons are involved in formation of covalent bonds is /are called :

Options

A. non-bonding electrons
B. lone pairs
C. unshared pairs
D. none of these

Answer

To solve the question regarding the valence electrons involved in the formation of covalent bonds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Valence Electrons**:
- Valence electrons are the electrons in the outermost shell of an atom that are involved in forming bonds with other atoms.

2. **Definition of Covalent Bond**:
- A covalent bond is formed when two atoms share one or more pairs of electrons. The electrons that are shared between the atoms are called bonding electrons.

3. **Analyzing the Options**:
- **A: Non-bonding electrons**: These are electrons that do not participate in bonding.
- **B: Lone pairs**: These are pairs of valence electrons that are not shared with another atom and thus do not participate in bonding.
- **C: Unshared pairs**: This term is synonymous with lone pairs, referring to non-bonding electrons.
- **D: None of these**: This option suggests that none of the previous definitions correctly describe the electrons involved in covalent bonding.

4. **Identifying the Correct Answer**:
- Since the question specifically asks about the electrons involved in the formation of covalent bonds, we focus on the term "bonding electrons."
- The options B and C refer to non-bonding electrons, which do not participate in covalent bonding.
- Therefore, the correct answer is **D: None of these**, as the valence electrons involved in covalent bonds are referred to as bonding electrons, which is not listed in the options.

### Final Answer:
The valence electrons involved in the formation of covalent bonds are called **bonding electrons**. Therefore, the correct answer is **D: None of these**.

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