The Periodic Table: chemical periodicity — Chemistry 9701 AS & A Level Question & Worked Solution

(a(i))

Using this table, choose one element for each description. Write the symbol of the element in every case. The element whose molecule contains exactly eight atoms.

(a(ii))

The element that produces the largest cation.

(a(iii))

An element which floats on water and also reacts with it.

(a(iv))

An element that reacts with water to produce a solution able to act as an oxidising agent.

(a(v))[5]

An element whose nitrate gives off a brown gas during thermal decomposition.

(b(i))

State the formula for the oxide of the most electronegative element.

(b(ii))[3]

Some of these elements make more than one acidic oxide. Give the formulae of two oxides made by the same element.

(c(i))

Give the formulae of two fluorides that may be ionic.

(c(ii))

What shape does the $\text{SF}_6$ molecule have?

(c(iii))[4]

In the series of fluorides above, the oxidation number of the elements rises from NaF to SF$_6$ and then drops at ClF$_5$. Attempts to make ClF$_7$ have not succeeded, but IF$_7$ has been made. Suggest an explanation for why IF$_7$ exists and why ClF$_7$ does not.

The Periodic Table: chemical periodicity — practice question

Worked solution & mark scheme