Chemical Bonding

Question 1

Define: Chemical Bond

Answer 1

The force that holds to or more atoms together in a stable molecule.

Question 2

Define: Electrovalent/Ionic Bonding

Answer 2

The transfer of electrons from a metallic atom to a non metallic atom to form an electrovalent/ionic compound.

Question 3

Define: Covalent Compound

Answer 3

The mutual sharing of electrons between two non-metallic atoms (generally) to form a covalent compound.

Question 4

Define: Coordinate Bond

Answer 4

A bond that has both properties of ionic bonds and covalent bonds.

Question 5

Formation of ionic Compound:
1. Lower the IP of metallic atom ______.
2. Higher the EA of non-metallic atom ______.
3. Larger the electronegativity difference between the two atoms _______.

Answer 5

1. greater the ease of cation formation.
2. greater the ease of anion formation.
3. electron transfer takes place easily.

Question 6

Explain: Non-Polar Covalent Compound

Answer 6

When shared pair of electrons are equally distributed between the two atoms.

No charge separation takes place the covalent molecule is symmetrical and electrically neutral.

Eg. H2, Cl2, O2, N2, CH4, CCl4

Question 7

Explain: Polar Covalent Compound

Answer 7

When shared pair of electrons are unequally distributed between the two atoms.

Charge separation takes place the atom that attracts electrons more strongly develops a slight negative charge.

Eg. H2O, NH3, HCL

Question 8

Formation of H3O+ and NH4+ ion

Answer 8

TB page 33

Question 9

Difference Between Ionic & Covalent compounds: State

Answer 9

I : Crystalline hard solids at room temperature.

C : Gas, Liquid or Soft Solid at room temperature.

Question 10

Difference Between Ionic & Covalent compounds: Volatility

Answer 10

I : Non - volatile

C : Volatile

Question 11

Difference Between Ionic & Covalent compounds:
Melting & Boiling Point

Answer 11

I : High because of strong electrostatic force of attraction.

C : Low because of weak VanderWaals force of attraction.

Question 12

Difference Between Ionic & Covalent compounds: Conduction of Heat

Answer 12

I : Good

C : Bad or Non

Question 13

Difference Between Ionic & Covalent compounds: Conduction of Electricity

Answer 13

I : Solid state - Non-conductors due to string electrostatic forces.
Molten or aqueous solution state - Good Conductors as electrostatic force is weakened forming free ions.

C : Non-Conductors
Non-polar covalent compounds (CCl4) contain molecules not free ions, polar covalent compounds (HCL, NH3) show charge separation and disassociate in H2O.

Question 14

Difference Between Ionic & Covalent compounds: Electrolysis

Answer 14

I : can be electrolysed in molten or aq.soln state. on electrolysis the ions being charged are attracted towards the respective electrodes.

C : Cannot be electrolysed in normal state, but polar covalent compounds in solution state undergo electrolysis (HCL, NH3).

Question 15

Difference Between Ionic & Covalent compounds: Solubility in Water

Answer 15

I : Soluble, due to high dielectric constant.

C : Polar are Soluble, Non-Polar are Insoluble.

Question 16

Difference Between Ionic & Covalent compounds:
Solubility in Inorganic Solvents
eg. Benzene, alcohol

Answer 16

I : Insoluble, due to low dielectric constants.

C : Polar are Insoluble, Non-Polar are Soluble.

Question 17

Difference Between Ionic & Covalent compounds: Reactions

Answer 17

I : Undergo high speed ionic reactions, due to free ions easily formed in solution and they rapidly regroup in solution.

C : Undergo slow speed molecular reaction, as covalent molecules are first broken and new bonds are slowly established.

Question 18

Electrovalent compounds undergo electrolytic dissociation on passage of electric current.

Process includes separation of ions already present in the ionic compound.

eg. NaCl

Answer 18

Covalent Compounds undergo ionisation in solution state on passage of electric current.

Process includes formation of ion from molecules which are not in ionic state.

eg. HCl