Sec 3 Combined Science (Chemistry) Bonding & Structure topical questions

Sodium (2.8.1) reacts with oxygen (2.8.6) to form sodium oxide. State the ions formed and the formula of sodium oxide.

State three general physical properties of metals.

Classify each as element, compound or mixture: (a) copper, (b) carbon dioxide, (c) sea water.

A dot-and-cross diagram for HCl shows hydrogen's electron as a dot and chlorine's seven outer electrons as crosses. State the total number of electrons shown in chlorine's outer shell in the molecule, and how many are shared.

Explain how a magnesium atom (2.8.2) and a fluorine atom (2.8.7) each reach a noble-gas arrangement when they react, and write the formula of the compound formed.

Describe the dot-and-cross diagram (outer shells only) for a molecule of carbon dioxide, and state the total number of shared electrons in the molecule.

Explain why sodium chloride conducts electricity when molten but not when solid.

Substance P is a gas at room temperature and does not conduct in any state. Substance Q melts at 1063 °C and conducts when molten. Classify both, quoting the data you used.

Phosphorus forms a chloride with formula PCl₃. Phosphorus has the electron arrangement 2.8.5 and chlorine is 2.8.7. Deduce the bonding in PCl₃ and explain why the formula is PCl₃ rather than PCl₅.

A student heats solid potassium iodide strongly. It first melts at 681 °C, and the melt conducts. The student concludes potassium iodide must contain free electrons like a metal. Evaluate the conclusion.

Compare the melting of ice and the boiling of water in terms of particles and bonds, and use the comparison to explain why water's boiling point (100 °C) is so much higher than its melting point (0 °C).

Two structure diagrams are described. Diagram X: identical atoms in perfectly regular rows. Diagram Y: regular rows of one atom type interrupted by scattered smaller atoms of a second type. Identify each diagram, state which material is malleable and which is harder, and explain both behaviours.