Chemical bonding：練習題

Which of the following atoms has the highest value of electronegativity?

Which statement correctly compares the bond length and bond energy in a molecule of nitrogen, \( N_2 \), with those in a molecule of oxygen, \( O_2 \)?

The bond energies of \( \text{H–Cl} \), \( \text{H–Br} \), and \( \text{H–I} \) are \( 431 \), \( 366 \), and \( 299 \text{ kJ mol}^{-1} \) respectively.
Which statement correctly relates the bond length to the thermal stability of these molecules?

Which molecule contains exactly two double covalent bonds and has a linear shape according to VSEPR theory?

In the dimer of aluminium chloride, \( \text{Al}_2\text{Cl}_6 \), which type of bond is formed when two \( \text{AlCl}_3 \) molecules join together?

Define the term electronegativity as it applies to a covalent bond between two atoms.

Using the Valence Shell Electron Pair Repulsion (VSEPR) theory, predict the shape and bond angle of an ammonia molecule, \(NH_3\).

Explain, in terms of structure and bonding, why graphite is able to conduct electricity while diamond acts as an electrical insulator.

(a) Define the term ionic bonding.
(b) Draw a dot-and-cross diagram to show the arrangement of electrons in the ionic compound calcium fluoride, \( CaF_2 \). Show all outer shell electrons.
(c) Explain, in terms of structure and bonding, why calcium fluoride has a high melting point.

(a) Define electronegativity and state the trend in electronegativity values across Period 3 of the Periodic Table. (2)

(b) Ammonia, \( \text{NH}_3 \), has a much higher boiling point than phosphine, \( \text{PH}_3 \). Identify the strongest type of intermolecular force present in ammonia and explain why this leads to a higher boiling point. (2)

(c) State the shape and the bond angle of the \( \text{NH}_3 \) molecule as predicted by the VSEPR theory. (1)