Explanation:
Non-metal elements bond to each other covalently. Ca3N2​ is made up of a metal and a nonmetal (with a large difference in electronegativity) and has ionic bonding.

Explanation:​
C3H6​ belongs to the alkene class with the general formula CnH2n​, and has a three carbon chain.

Explanation​:
Neither material is electrically conductive. Diamond has no delocalized electrons, while the delocalized electrons in buckminsterfullerene are confined within the molecule. There is no extended lattice of bonds through which the electrons can move in response to an applied potential difference. Diamond is a hard material; a large force is required to break the strong covalent bonds between atoms.

Buckminsterfullerene, however, is soft, as only a small force is needed to overcome the weak intermolecular (London / dispersion) forces between molecules.

This question is moderately difficult, as the student must recall multiple features of the two carbon allotropes or deduce their physical properties from the diagrams given.

Explanation:​

Lithium is in group 1 and so forms Li+ ions. The formula of the nitride ion is N3−as nitrogen is in group 15. For the positive and negative charges to cancel out, three Li+ ions are needed for each N3− ion.

Explanation​:
Oxidation reaction; Magnesium is much less electronegative than oxygen, so the Mg atoms lose electrons to the O atoms during the reaction. This process forms positive Mg2+ ions, termed cations, and negative O2− ions, termed anions.

This question is categorized as easy, as the student must recall two pieces of information that are covered extensively in the syllabus.

Explanation​:
There is no polyatomic ion with the formula of CO4 ^2−​. The correct formula for the carbonate ion is CO3^2−​. The formulas and charges of the other ions are correct.

Explanation​:
Metals and non-metals have the greatest differences in electronegativity and so ionic bonds are formed.

Explanation​:
Carboxylic acids have hydrogen bonding due to O−H bonds.

Explanation​:
Simple molecular covalent structures cannot conduct electricity due to an absence of charged particles. $\mathrm{NaCl}$ is an ionic compound that has ions that are free to move when in a molten state.

Explanation​:
Choice A refers to ionic bonding;
Choice B could refer to ionic bonding or specifically coordinate (dative) bonding;
Choice C refers to hydrogen bonding.

Explanation:​
Across the same period, metals have lower ionization energies than non-metals due to lower nuclear charges with the same number of shells (shielding effect).

Explanation​:
There is no polyatomic ion with the formula of CO42−COX42−​. The correct formula for the carbonate ion is CO32−COX32−​. The formulas and charges of the other ions are correct.

Explanation:​
Recall of description of metallic bonding as positive ions surrounded by delocalized electrons.

Explanation:​
To answer this question, the student must apply the data to the van Arkel-Ketelaar triangle to determine the type of bonding present in the molecule.

The bonding triangle analysis shows that the material is an ionic compound. Therefore, characteristic properties include that it is a crystalline lattice with a high melting point.

This question is categorized as easy since the student only needs to apply the data to Section 17 of the data booklet and then recall the basic properties of matter.

Explanation​:
NH3​ has all of the bonds/forces named above, but its high boiling point is due to the presence of hydrogen bonds which are the strongest intermolecular forces. Hydrogen bonding is possible due to the presence of N−H bonds.

Explanation​:
Volatility refers to the ease at which a substance vaporizes. Ionic bonds are very strong and, therefore, a lot of energy is required to turn ionic compounds into gases.

Polar solvents are able to form electrostatic forces of attraction with ions.

Explanation​:
There is a non-bonding (lone) pair of electrons on the nitrogen atom and three on each chlorine. There are three N−Cl bonding pairs of electrons. Only the outermost electrons are shown for each element

Explanation:​
All three central atoms (N, C, and O) have four electron domains. An increasing number of lone pairs reduces the angle between the bonding pairs.
In CH4​ there are no lone pairs and it has a tetrahedral shape with bond angles of 109.5$°$.
In NH3​ there is one lone pair and it has a trigonal pyramidal shape with bond angles of 107°.
In H2​O, there are two lone pairs, and it has a bent shape with bond angles of 104.5$°$.

Explanation:​
There are three bonding pairs and no lone pairs around the central B atom giving it a trigonal planar shape. As this is symmetrical, there is no net dipole even though the individual bonds are polar. There are only six electrons around the central B atom making it electron deficient (it has not achieved its octet).

Explanation​:
All statements are correct, but only D is a reason for solubility in water

Explanation:​
Graphite is made up of individual graphene layers. Both have carbon atoms with three electron domains and trigonal planar shapes. Each carbon atom in diamond has four electron domains resulting in tetrahedral arrangements.