Define a chemical bond.

A chemical bond is the force that holds atoms together in a molecule or compound.

What are the primary theories that explain how atoms bond?

Chemical bonding is explained using different models, including the Kössel-Lewis theory, Valence Shell Electron Pair Repulsion (VSEPR) theory, Valence Bond (VB) theory, and Molecular Orbital (MO) theory.

How does the octet rule explain the stability of atoms?

The octet rule states that atoms tend to gain, lose, or share electrons to achieve eight valence electrons, similar to noble gases.

What is meant by an ionic bond?

An ionic bond is formed when one atom transfers electrons to another, resulting in positive and negative ions held together by electrostatic attraction.

How does a covalent bond differ from an ionic bond?

A covalent bond occurs when two atoms share electrons instead of transferring them, as seen in molecules like H₂ or O₂.

What distinguishes a coordinate bond from a regular covalent bond?

In a coordinate bond, both shared electrons originate from the same atom, whereas in a covalent bond, each atom donates an electron to the bond.

What are Lewis symbols used for?

Lewis symbols are a way to represent valence electrons around an atom using dots.

Describe the Lewis structure of carbon dioxide (CO₂).

CO₂ is represented as O=C=O, where carbon forms two double bonds with oxygen atoms.

Explain what is meant by bond length.

Bond length is the fixed distance between the nuclei of two atoms connected by a bond.

What is the concept of resonance in molecules?

Resonance occurs when multiple Lewis structures are required to describe a molecule accurately.

Define hybridization in simple words.

Hybridization is the mixing of atomic orbitals to form new, equivalent orbitals for bonding.

What type of hybridization does carbon exhibit in CH₄?

In methane (CH₄), carbon undergoes sp³ hybridization to form four equivalent bonds.

What is the molecular shape of ammonia (NH₃)?

NH₃ has a trigonal pyramidal shape due to lone pair repulsion.

Why is the H₂O bond angle 104.5° instead of 109.5°?

The two lone pairs on oxygen repel the bonding pairs, pushing them closer together.

What does the Molecular Orbital Theory propose?

It suggests that atomic orbitals combine to form molecular orbitals, which can be bonding or antibonding.

Calculate the bond order of an oxygen molecule (O₂).

The bond order of O₂ is 2, determined using MO theory.

Define hydrogen bonding with an example.

Hydrogen bonding is an attractive force between hydrogen and highly electronegative elements like O, N, or F (e.g., in water, H₂O).

How is dipole moment mathematically represented?

μ = Q × r
where Q is the charge, and r is the distance between charges.

Why does NH₃ have a higher dipole moment than NF₃?

In NH₃, the lone pair dipole aligns with the bond dipoles, reinforcing the dipole moment. In NF₃, the lone pair dipole opposes the bond dipoles, reducing the overall dipole moment.