Chemical Bonding and Molecular Structure

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (i)

The electronic configuration of A 1S² 2S²  2P⁶  is having no unpaired electrons in the outer most shells. So, an atom having no unpaired electron in its valence shell is said to be stable.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (ii)

For a molecule having a hybridization of sp², its geometry in plane is trigonal planar. For a molecule having a trigonal planar geometry, its bond angle will be 120°

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (iv)

The electrons involved in the formation of any chemical bond are the valence shell electrons. In the given electronic configuration,1s² 2s² 2p⁶ 3s² 3d² 4s² the valence shell electrons are in d-orbital and s-orbital. So, the four electrons involved in the chemical bond formation will be 3d² 4s².

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (ii)

Hydrogen bond is the strongest in that molecules have a higher difference in electronegativity. Due to the small size of the oxygen atom, it has the highest electronegative character. So, H₂O molecules will have the strongest hydrogen bonding

HCl, HI and H₂Sdo not have hydrogen bonding between their atoms. So, H₂O will have the strongest hydrogen bonding.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (iii)

(i) The molecule XeF₄ has a square planar geometry and the bond lengths of all the fluoride atoms attached to xenon atoms are equal.

(ii) The molecule BF₄ ^- has a tetrahedral geometry and the bond lengths of all the fluoride bonds attached to boron are equal.

(iii) In the molecule C₂H₄ all the bonds are not equal. The bond length of the double bond between the carbon atoms is 134 pm and the bond length of CH- is 110 pm.

(iv) The molecule SiF₄ has a tetrahedral geometry and the bond lengths of all the fluoride atoms attached to silicon atoms are equal.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (iii)

The molecular orbital diagram of O₂^2-,   π^∗2Px and π^∗2Py molecular orbitals are completely filled, which are partially filled in O2. These are no unpaired electrons. So,  O₂^2-does not contain unpaired electrons.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (iii)

A double bond has one s bond and one π bond. In the above given structure 5π bonds are present. The s bonds are the additions of all the single bonds in the structure. There are 19s bonds in the above given structure.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (i)

(i) The molecule of BH₄ ^- has four bond pairs and zero lone pair of electrons, so it will be a tetrahedral molecule.

(ii) NH₂ ^- has two bond pairs and two lone pairs of electrons on the nitrogen atom. So, it will have a bent geometry.

(iii) CO₃ ^2- has three bond pairs and no lone pairs of electrons on carbon atoms. So, it will have a trigonal planar geometry.

(iv) H₃O⁺ has three bond pairs and one lone pair of electrons on oxygen atoms. So, it has a pyramidal geometry.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (iv)

The number of bond pairs on the nitrogen atom of NO₃^-  are 4 and the structure of - NO₃ does not have any lone pairs of electrons. The structure of  NO₃^- molecule is:

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option (ii)

In a polyatomic molecule or an ion, the formal charge of an atom is defined as the difference between the valence electrons present in that atom and the number of electrons assigned to that atom in the Lewis structure.

Formal charge = No. of valence electrons - (No. of lone pair $+\frac{1}{2}Nbelectrons)$

Formal Charge = 6 - $\left(6+\frac{1}{2}*2\right)$

Formal Charge = -1