The Periodic Table — GCSE Chemistry practice questions

Question 1

Which statement about the Periodic Table is correct?

Accepted Answer

C: For an element in Groups I to VII, the group number equals the number of outer-shell electrons.. The table is arranged in order of increasing proton number, not relative atomic mass. Elements in the same group, not the same period, have the same number of outer-shell electrons, and for Groups I to VII this number equals the group number. Metallic character decreases across a period.

Question 2

Nickel is used as a catalyst when vegetable oils are hardened to make margarine. Nickel is a transition element.

Which row describes nickel and its compounds?

Accepted Answer

A: high · high · coloured. Transition elements such as nickel have high densities and high melting points, and their compounds are coloured (nickel compounds are often green). They and their compounds are also often catalysts.

Question 3

A newly described element, code-named Q, has these properties.

- It is a dark-coloured solid at r.t.p.
- It does not conduct electricity.
- Its oxide dissolves in water to give a solution of pH 3.
- It forms a compound with calcium with the formula CaQ₂.

In which part of the Periodic Table is Q most likely to be?

Accepted Answer

C: Group VII. Q does not conduct and has an acidic oxide, so it is a non-metal. Calcium ions are 2+, so two Q ions balance one calcium ion: each Q ion is 1−, which is typical of Group VII. A dark solid non-metal in Group VII fits iodine-like behaviour.

	density	melting point	colour of its compounds
A	high	high	coloured
B	high	low	white
C	low	high	coloured
D	low	low	white