7 Most VSAQ’s of Chemical Bonding Chapter in Class 10th Physical Science (TS/AP)

2 Marks

VSAQ-1 : What is Lewis symbol of elements?

Definition of Lewis Symbol

  1. A Lewis symbol is a notation method representing the valence electrons of an atom or a simple ion.
  2. The valence electrons are depicted as dots (.) or crosses (x) placed around the chemical symbol of the element.

Purpose and Visualization:

Lewis symbols provide a simple and visual way to depict the arrangement of valence electrons in an atom or ion.

VSAQ-2 : Explain, why bonding angle HOH in water is 104°31 instead of 109° 28?

Bonding Angle in Water (H2O)

  1. The bond angle in H2O is 104° 31′, narrower than the ideal 109° 28′.
  2. This is due to lone pair-lone pair and lone pair-bond pair repulsions on the oxygen atom.
  3. These repulsions compress the bond angle, resulting in water’s unique bent shape.

VSAQ-3 : Draw the structure of the methane molecule. Write its bond angle.

Structure of Methane Molecule (CH4)

  1. Molecular Structure:
    • The methane molecule (CH4​) has a tetrahedral structure.
    • Carbon (C) is at the center, with four hydrogen (H) atoms symmetrically bonded to it.
  2. Bond Angle: The bond angle between hydrogen atoms in methane is 109° 28′.

VSAQ-4 : How is a sigma bond formed?

Sigma Bond Formation:

  1. A sigma (σ) bond is formed by the axial or head-on overlap of pure or hybrid orbitals from two atoms.
  2. This bond results from direct overlap of atomic orbitals along the internuclear axis between the bonding atoms.
  3. It creates a strong and stable covalent bond.

VSAQ-5 : What is the difference between lone pair and bond pair of electrons?

Difference Between Lone Pair and Bond Pair Electrons

  1. Lone Pair Electrons
    • Non-Bonding: Lone pair electrons do not participate in bond formation.
    • Existence: They are found in the outer shell of an atom, not shared with another atom.
  2. Bond Pair Electrons
    • Bond Formation: Bond pair electrons are involved in bonding between atoms.
    • Shared Electrons: These are electrons that are shared between two atoms, forming a bond.

VSAQ-6 : Define Co-ordination number.

Coordination Number:
Refers to the number of oppositely charged ions surrounding a given ion with a specific charge in a chemical compound or crystal lattice.

VSAQ-7 : NH3 has higher boiling point than PH3. Give reason.

Reason for Higher Boiling Point in NH3:
NH3 (Ammonia) has a higher boiling point than PH3 (Phosphine) primarily because NH3 can form hydrogen bonds, a strong type of intermolecular force, while PH3 cannot.