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During the formation of sodium chloride sodium atom donates electron and gets converted to sodium ion (Na⁺) chlorine accepts an electron to form chloride ion (Cl^-). Through this sodium and chlorine atoms complete an octet in their outermost shell to attain stability. 

The oppositely charged ions thus formed are held together by electrostatic force of attraction. This attractive force is called Ionic Bond. Sodium chloride contains ionic bond.

The number of electrons which an atom gains or loses or shares with other atoms to attain noble gas configuration is termed its valency.

Correct option is  B) 1, 2

Sigma bond is a bond formed by the overlapping of atomic orbital along the axis.

Yes. The values are not different for the bonds between different types of atoms

It is defined as the “angle between the orbitals containing bonding electron pairs around the central atom in a molecule or in a complex ion”. It is expressed in degrees. 

Example: In CO₂ the bond angle is 180°. So CO₂ has linear shape.

The ground state electronic configuration of C is 1s²2s²2p². In exited state, one electron if 2s jumps to 2p, hence the electronic configuration 1s² 2s¹2p¹_x 2p¹_y 2p¹_z

  Correct option is  A) 1,1

(i) Sigma bond-overlapping of orbital along the axis.

(ii) pi bond overlapping sideways of two p-orbital.

There are two ways of formation of chemical bonds :

1. by loss and gain of electrons 

2. by sharing a pair of electrons between the two atoms.

In either process of formation of chemical bond, each atom attains a stable noble gas electronic configuration.

The electrons present in the outermost shell of an atom are involved in the formation of a chemical bond.

The valence shell configuration of hydrogen atom is 1s¹. 

Two hydrogen atoms approach each other and share their valence electrons. 

By having two electrons in its valence shell,

H atom attains the nearest noble gas configuration of He. 

H₂ molecule attains stability due to duplet formation. 

Hence,

H₂ is stable even though it never satisfies the octet rule.

Bond length increases with increase in size of atom. Cl atom is smaller than Br atom. 

Hence, 

Cl-Cl covalent bond length is smaller than Br-Br covalent bond length.

Covalent bond is formed by sharing of electrons.

2 electrons in the outer shell of each nitrogen atom are not involved in sharing during formation of nitrogen molecule.

(a) s – s 

(b) p – p 

(c) s – p

In ethyne, each carbon atom is sp-hybridised  giving a linear structure. 

Electrostatic force: Force of attraction between positively charged and negatively charged bodies or ions is called electrostatic force.

Cation: It is a positively charged ion formed by the removal of an electron from an atom.

The anion of Na₂O₂ is O₂²⁻ (peroxide ion)

Electronic Configuration –

₈O⁻ = 9 = 2,7 = 1s² , 2s²2p⁵

₈O⁻ = 9 = 2,7 = 1s² , 2s²2p⁵

Molecular Orbital Configuration

(σ1s)² , (σ1s)² , (σ2s)² , (σ*2s)² , (σ2pz)² , (π2px)² = (π2py)²(π*2px)² = (π²2py)² , (σ*2pz)⁰

Since, there is no unpaired electron present in molecular orbital, so it diamagnetic in nature.

Anion: It is a negatively charged ion formed by the addition of an electron to the atom.

An anion is formed when an atom gains electrons

Ionic compounds are more soluble in polar solvents.

Key ideas of MO Theory :

• MOs in molecules are similar to AOs of atoms. Molecular orbital describes region of space in the molecule representing the probability of an electron.
• MOs are formed by combining AOs of different atoms. The number of MOs formed is equal to the number of AOs combined.
• Atomic orbitals of comparable energies and proper symmetry combine to form molecular orbitals.
• MOs those are lower in energy than the starting AOs are bonding MOs and those higher in energy are antibonding MOs.
• The electrons are filled in MOs beginning with the lowest energy.
• Only two electrons occupy each molecular orbital and they have opposite spins, that is, their spins are paired.
• The bond order of the molecule can be calculated from the number of bonding and antibonding electrons.

B) σ sp³ – s bonds

The attractive forces which hold the constituent atoms in molecules of species in lattices etc., is called a chemical bond. 

They are of the following types: 

(i) Electrovalent or ionic bond 

(ii) Covalent bond 

(iii) Coordinate or dative bond 

(iv) Metallic bond 

(v) Hydrogen bond 

(vi) van der Waals forces.

A chemical bond is formed by mutual sharing or by transfer of one or more electrons. In doing so, each combining atom acquires stable noble gas electronic configuration having 8 electrons in its outermost shell.

The attractive force which holds various constituents (atoms, ions etc.) together in different chemical species is called a chemical bond.

The chemical force which keeps the atoms in any molecule together is called a chemical bond.

During a chemical reaction the atoms tend to adjust their electronic arrangement in such a way that they achieve 8 e^- in their outermost electron. This is called octet rule.

No. Because to form an ionic compound if one element gives electrons, the other element should accept electrons. Metals can only lose electrons to provide +ve ions.

Yes. There are elements which exist as atoms.

Solid  state. 

Atoms exist as a single atom, sometimes as a group of atoms also.

They may exist as a single atom or as a group of atoms.

D) a → iii, b → i, c → ii

 Correct option is  C) 3

The electrostatic attractive force that keeps cation and anion together to form a new electrically neutral compounds is called ionic bond.

The number of electrons gained by a non-metal element for its atom is its valency, which is equal to 8 – its group number. 

Ex : The valency of chlorine is (8 – 7) = 1.

There are three sigma and two pi-bonds in C₂H₂. 

There are five sigma bonds and one pi-bond in C₂H₄.

In a molecule of ethane, there are 5 σ - bonds (one between C-C , and four between C-H and one π- bond.

In a molecule of ethene; there are 5 σ-bonds. (One between C - C, and four between C - H) and one π-bond.

N₂ = (σ1s)² (σ*1s)² (σ2s)² (σ*2s)²

(σ2p_x)² (π2p_y)² (π2p_z)²

Bond order = 1/2 (N_b - N_a) = 1/2 (10 - 4) = 3

N₂⁺ = (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (π2p_x)² [π2p_y]² [σ2p_z]¹

Bond order = 1/2 (7 - 2) = 2.5

Hence bond order of N₂ is greater than N₂⁺

O₂⁺ = (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (σ2p_x)² (π 2p_y)² (2π 2p_z)² (π* 2p_y)¹

Bond order = 1/2 (N_b - N_a) = 1/2 (10 - 5) = 2.5

Hence Bond order of O₂ is less than of O₂⁺.

1. In case of water, hydrogen bonding causes association of the H₂O molecules. There is no such hydrogen bonding in H₂S, that is why it is a gas. 

2. There is hydrogen bonding in NH₃ but not in PH₃ .

In covalent molecule the combining atoms should have 

1. High ionization energy 

2. High electron affinity 

3. Small or equal electronegative 

4. Smaller atomic size 

5. Contain unpaired electron with opposition spin 

6. Attain octect structure. 

7. Smaller Intermolecular distance.

Ionic bond formation mainly depends upon three factors –

(i) Low ionization energy – elements with low ionization enthalpy have greater tendency to form an ionic bonds.

(ii) High electron gain enthalpy – high negative value of electron gain enthalpy favours ionic bond.

(iii) Lattice energy – high lattice energy value favours ionic bond formation.

The pair of electron which involves in hybridization but not involves in covalent bond formation (involves in co-ordinate bond formation).

1. They have high Melting point. 

2. Many of it are solid in nature. 

3. Does not conduct in solid state but good conductors in fused or aqueous state.

4. Soluble in polar solvent & insoluble in non-polar solvent.

5. Ionic bond is non-directional. 

6. They do not exhibit Isomerism.