The table below shows the atomic numbers of elements T, U, V and W. Study it and answer the questions that follow. The letters are not the actual symbols of the elements. (a) What type of bond would be formed between:- (i) elements U and W

Here are the solutions to your questions:

8. The table shows the pH values of solutions A to E

• 8a) Which solution is likely to be rain water? Rainwater is typically slightly acidic due to dissolved carbon dioxide, with a pH usually around 5.6. Solution A has a pH of 6, which is slightly acidic and closest to the expected pH of rainwater. Solution: $\boxed{\text{A}}$

• 8b) Which solution would be most suitable for making anti-acid tablets? Anti-acid tablets are used to neutralize stomach acid, so they must be basic. Solution B has a pH of 13, indicating it is a strong base, making it most suitable. Solution: $\boxed{\text{B}}$

• 8c) What will be the pH value of the mixture of C and B? Solution C has a pH of 2 (strong acid), and Solution B has a pH of 13 (strong base). When a strong acid and a strong base are mixed, they undergo a neutralization reaction. Assuming appropriate concentrations and volumes, the resulting mixture would be neutral. pH value: $\boxed{\text{7}}$

9. The diagram below shows a Bunsen Burner when in use.

• Which of the labeled parts is used for heating? Give a reason. The labeled part used for heating is A. Reason: Part A represents the outer, non-luminous cone of the flame, which is the hottest part because it allows for complete combustion of the gas due to a sufficient supply of oxygen.

10. The table below shows the atomic numbers of elements T, U, V and W. Study it and answer the questions that follow. The letters are not the actual symbols of the elements.

Element	T	U	V	W
Atomic number	13	16	17	20

• 10a) What type of bond would be formed between:-
  • (i) elements U and W Element U has an atomic number of 16, so its electron configuration is 2, 8, 6. It is a non-metal and tends to gain 2 electrons to achieve a stable octet. Element W has an atomic number of 20, so its electron configuration is 2, 8, 8, 2. It is a metal and tends to lose 2 electrons to achieve a stable octet. When a metal (W) reacts with a non-metal (U), electrons are transferred, forming an ionic bond. Type of bond: $\boxed{\text{Ionic bond}}$