Bonding：练习题

Which of the following substances contains only induced dipole-dipole forces (van der Waals forces) between its molecules?

In which of the following species does the central atom possess exactly one dative covalent (co-ordinate) bond formed by accepting an electron pair?

Arrange the following species in order of decreasing bond angle around the central nitrogen atom:
\(NH_4^+\), \(NH_3\), \(NH_2^-\)

Which molecule has a non-zero permanent dipole moment?

What is the molecular shape and the bond angles present in a molecule of phosphorus pentachloride, \(PCl_5\)?

Describe the nature of the chemical bonding found in a lattice of magnesium.

A dative covalent (co-ordinate) bond is formed when a molecule of boron trifluoride, \(\text{BF}_3\), reacts with a fluoride ion, \(\text{F}^-\), to form the tetrafluoroborate ion, \(\text{BF}_4^-\).
Explain how this co-ordinate bond is formed in terms of electron pairs.

State the type of crystal structure shown by silicon dioxide, \(\text{SiO}_2\), and explain why it has a high melting point.

The ammonia molecule (\(\text{NH}_3\)) and the ammonium ion (\(\text{NH}_4^+\)) are both composed of nitrogen and hydrogen atoms.
(a) State the number of bonding pairs and lone pairs of electrons around the central nitrogen atom in the ammonia molecule.
(b) Predict the shape and the bond angle of the ammonia molecule, explaining your choice in terms of electron pair repulsion.

The shapes of molecules and ions can be predicted using the Valence Shell Electron Pair Repulsion (VSEPR) theory.
(a) State the number of bonding pairs and lone pairs of electrons around the central iodine atom in the \(ICl_4^-\).
(b) Name the shape of the \(ICl_4^-\) ion and state the bond angle(s) present.
(c) Explain why \(ICl_4^-\) adopts this specific shape instead of a tetrahedral arrangement, referring to electron pair repulsion in your answer.