Chemical Bonding
Chapter 5: Chemical Bonding
- The bond order of the superoxide ion O2− is Answer: D. 1.5 O₂⁻ has 17 electrons: bonding 10, antibonding 7. Bond order =10-7/2=1.5 . 1
- The shape of the ClF3 molecule is Answer: B. T-shaped Cl has 3 bond pairs and 2 lone pairs (sp³d). The lone pairs occupy equatorial positions, giving a T-shape. 1
- Predict the shape and bond angles in the following molecules: a. CF4 b. NF3 c. HCN d. H2 S CF₄: tetrahedral, 109°28′; NF₃: trigonal pyramidal, about 102°; HCN: linear, 180°; H₂S: bent (angular), about 92°. a. CF₄ : C has 4 bond pai... 1
- Define : a. Bond Enthalpy b. Bond Length a. Bond enthalpy is the amount of energy required to break one mole of bonds of a particular type between two atoms in the gaseous state. It... 1
- In case of bond formation in Acetylene molecule : a. How many covalend bonds are formed ? Acetylene ( mathrmH-CequivC-H ): a. 5 covalent bonds; b. 3 σ bonds and 2 π bonds; c. sp hybridisation. a. There are two C–H single bonds and... 1
- BF3 molecule is planar but NH3 pyramidal. Explain B in BF₃ is sp² hybridised with no lone pair, so BF₃ is trigonal planar; N in NH₃ is sp³ hybridised with one lone pair, so NH₃ is pyramidal.... 1
- F-Be-F is a liner molecule but H-O-H is angular. Explain. In BeF₂ , Be is sp hybridised with no lone pairs, so the molecule is linear (180°); in H₂O , O is sp³ hybridised with two lone pairs, so the... 1
- Identify the type of orbital overlap present in a. H2 b. F2 c. H-F molecule. Explain diagramatically a. H₂ : s–s overlap. b. F₂ : p–p (head-on) overlap. c. HF: s–p overlap. All three bonds are σ bonds. H₂ (s–s): each H has a half-filled sphe... 1
- Which type of hybridization is present in ammonia molecule? Ammonia has sp³ hybridisation; its shape is trigonal pyramidal with an H–N–H bond angle of about 107°. Nitrogen (Z = 7) is 1s²2s²2p_x¹2p_y¹2... 1
- Give reasons for: a. Sigma (σ)bond is stronger than Pi (π)bond. b. HF is a polar molecule a. Sigma (σ) bond is stronger than pi (π) bond. A σ bond is formed by head-on (axial) overlap of orbitals along the internuclear axis, so th... 1
- In Ammonia molecule the bond angle is 1070 and in water molecule it is Both N in NH₃ and O in H₂O are sp³ hybridised, but they have different numbers of lone pairs, and lone pairs repel more strongly than bond p... 1
- Explain geometry of methane molecule on the basis of Hybridisation In methane the carbon atom is sp³ hybridised, so the molecule is tetrahedral with all H–C–H angles equal to 109°28′. Ground state of C: 1s²2... 1
- Give reasons for need of Hybridisation Hybridisation is needed to explain the observed valency, the equivalence of bonds and the shapes (bond angles) of molecules, which the simpl... 1
- Explain in brief with one example: a. Ionic bond b. covalend bond c. co-ordinate bond a. Ionic bond: a bond formed by the complete transfer of one or more electrons from one atom (usually a metal) to another (usually a non-met... 1
- State octel rule. Explain its inadequecies with respect to The octet rule states that elements gain or lose electrons to attain an electron configuration of the nearest noble gas. Incomplete Octet: T... 2
- Display electron distribution around the oxygen atom in water molecule and state shape of the molecule, also write H-O-H bond angle. The shape of the water molecule is tetrahedral, and bond angle is 104.5 degrees. The electron distribution on the oxygen atom in a water mol... 2
- Distinguish between sigma and pi bond Sigma (σ) Bond Pi (π) Bond (a) the bond is formed by the axial overlap of the atomic orbitals The bond is formed by the sidewise overlap of... 1
- Draw Draw orbital diagrams of a. Fluorine molecule b. Hydrogen fluoxide molecule Both F₂ and HF are formed by head-on (axial) overlap of half-filled orbitals: p–p overlap in F₂ and s–p overlap in HF, giving a σ bond in ea... 1
- Draw Lewis electron dot structures of a. HF b. C2 H6 c. C2 H4 d. CF3 Cl e. SO2 Lewis structures (dots = valence electrons; a shared pair between two atoms is one bond): a. HF: H and F share one pair; F keeps three lone... 1
- Draw Diagram for bonding in ethene with sp2 Hybridisation. In ethene ( mathrmCH₂=CH₂ ) each carbon is sp² hybridised; the C=C double bond is one σ bond (sp²–sp² overlap) and one π bond (sideways over... 1
- Draw Lewis dot diagrams for the folowing a. Hydrogen (H2 ) b. Water (H2 O) Lewis dot diagrams show the valence electrons of each atom as dots; a shared pair between two atoms is a covalent bond. a. Hydrogen, H₂ : ea... 1
- Select and write the most appropriate alternatives from the given choices. A. Which molecule is linear? question Answer A b B a C b D a E c F d 1