e) Give the shapes of the following molecules:

Here are the solutions to the chemistry questions:

e) Give the shapes of the following molecules:

i) $\text{CO}_2$:
The carbon dioxide molecule has a central carbon atom double-bonded to two oxygen atoms. There are no lone pairs on the central carbon atom.
The shape is linear.

ii) $\text{CH}_4$:
The methane molecule has a central carbon atom single-bonded to four hydrogen atoms. There are no lone pairs on the central carbon atom.
The shape is tetrahedral.

iii) $\text{NH}_3$:
The ammonia molecule has a central nitrogen atom single-bonded to three hydrogen atoms and one lone pair of electrons.
The shape is trigonal pyramidal.

f) Apart from carbon, name two elements which exhibit allotropy.

• Sulfur
• Phosphorus

g) State three characteristic properties of transition metals.

• They form colored compounds.
• They exhibit variable oxidation states.
• They act as catalysts.

h) Name two metals which could be extracted by electrolysis.

• Aluminum
• Sodium

i) Define the term atomic number.
The atomic number is the number of protons found in the nucleus of an atom. It uniquely identifies a chemical element.

j) Name the types of chemical bonds present in $\text{NH}_4\text{Cl}$.

• Ionic bond (between $\text{NH}_4^+$ and $\text{Cl}^-$)
• Covalent bond (between N and H atoms within $\text{NH}_4^+$)
• Dative (coordinate) covalent bond (one of the N-H bonds in $\text{NH}_4^+$)