Chemical bonding：練習題

Which statement correctly describes metallic bonding?

In which of the following molecules or ions are all the bond angles approximately \(120^{\circ}\)?

Consider the following average bond energies (in kJ mol^-1):
C-C: 348
C=C: 614
C≡C: 839

Which statement about the reactivity of ethene (C₂H₄) compared to ethane (C₂H₆) and ethyne (C₂H₂) is correct?

Which statement best describes the nature of ionic bonding?

What is the shape and bond angle of the trichloromethyl radical, CCl₃^•, according to VSEPR theory?

Explain the bond angle in a water molecule (\(\text{H}_2\text{O}\)) using VSEPR theory.

Explain why the boiling point of ammonia, \(\text{NH}_3\), is significantly higher than that of phosphine, \(\text{PH}_3\), by referring to the specific intermolecular forces present in each substance.

Identify the hybridisation of the carbon atoms in a molecule of ethene, \(\text{C}_2\text{H}_4\), and describe the arrangement of the resulting hybrid orbitals around each carbon atom.

(a) Define the term electronegativity.
(b) Draw a dot-and-cross diagram to show the arrangement of the outer shell electrons in a molecule of nitrogen trifluoride, \( \text{NF}_3 \).
(c) Predict whether a molecule of \( \text{NF}_3 \) has a permanent dipole moment. Explain your answer briefly by referring to its shape.

(a) The nitrogen molecule, \( \text{N}_2 \), is very unreactive due to the strength of its triple bond. Describe the formation of this triple bond in terms of the number and type of orbital overlaps (\( \sigma \) and \( \pi \) bonds).
(b) Phosphorus forms a stable pentachloride, \( \text{PCl}_5 \).
(i) State the shape and all the bond angles present in a molecule of \( \text{PCl}_5 \).
(ii) Explain, with reference to the electronic configuration of phosphorus, how it is able to form five covalent bonds, whereas nitrogen can only form three.