CAIE IGCSE Chemistry Atoms Elements and Compounds Questions

Practise classifying substances, interpreting atoms and ions and connecting ionic, covalent and metallic structures with properties throughout this unit.

Covered syllabus points

2.1 Elements, compounds and mixtures 2.2 Atomic structure and the Periodic Table 2.3 Isotopes 2.4 Ions and ionic bonds 2.5 Simple molecules and covalent bonds 2.6 Giant covalent structures 2.7 Metallic bonding

[Maximum number: 2]

A list of substances is shown.
> ammonia bauxite carbon dioxide carbon monoxide ethanol hematite oxygen sodium chloride sulfur dioxide

Answer the questions using the list of substances.
Each substance may be used once, more than once or not at all.
State which substance is:

(a)

an element ..... [1]

[ 1 ]

(b)

an ionic compound ..... [1]

[ 1 ]

[Maximum number: 11]

This question is about elements X, Y and Z.

(a)

An atom of element X is represented as ${ }_{16}^{34} \mathbf{X}$ .

[ 5 ]

(i)

Name the different types of particles found in the nucleus of this atom of X.

[ 2 ]

(ii)

What is the term for the total number of particles in the nucleus of an atom?

[ 1 ]

(iii)

What is the total number of particles in the nucleus of an atom of ${ }_{16}^{34} \mathbf{X}$ ?

[ 1 ]

(iv)

What is the electronic structure of the ion $\mathbf{X}^{2-}$ ?

[ 1 ]

(b)

What term is used to describe atoms of the same element with different numbers of particles in the nucleus?

[ 1 ]

(c)

Part of the definition of relative atomic mass is 'the average mass of naturally occurring atoms of an element'.

Some relative atomic masses are not whole numbers.
Element Y has only two different types of atom, ${ }^{69} \mathbf{Y}$ and ${ }^{71} \mathbf{Y}$ .
The ratio of atoms present in element Y is shown.

{ }^{69} \mathbf{Y}:{ }^{71} \mathbf{Y}=3: 2

- Calculate the relative atomic mass of element Y to one decimal place.
relative atomic mass =
- Identify element Y.

[ 3 ]

$\text { M1 }(3 \times 69)+(2 \times 71)$ $\mathrm{M} 2=\frac{349}{5}=69.8$

M3 Y=Ga / gallium

(d)

Element Z is in Period 3 and Group V.

[ 2 ]

(i)

Explain in terms of electron transfer why Z behaves chemically as a non-metal.

[ 2 ]

[Maximum number: 14]

The Periodic Table is a method of classifying elements.

(a)

Calcium is in Group II and chlorine is in Group VII of the Periodic Table.

Explain, in terms of number of outer shell electrons and electron transfer, how calcium atoms and chlorine atoms form ions. Give the formulae of the ions formed.

[ 5 ]

Ca has 2 and Cl has outer electrons 7 (1)

Ca (atoms) lose electrons (1)

Cl (atoms) gain electrons (1)

$\mathrm{Ca}^{2+}$ (ions) (1)

Ct (ions) (1)

(b)

Group V chlorides are covalent molecules. The boiling points of some Group V chlorides are shown.

Table for Question (b) — CAIE IGCSE Chemistry

[ 5 ]

(i)

Explain the trend in boiling points in terms of attractive forces between particles.

[ 2 ]

(ii)

Complete the dot-and-cross diagram to show the electron arrangement in a molecule of $\mathrm{PCl}_{3}$ .

Show outer electrons only.

Figure for Question (ii) — CAIE IGCSE Chemistry

[ 3 ]

(c)

Lithium fluoride has ionic bonding.

[ 4 ]

(i)

What is an ionic bond?

[ 2 ]

(ii)

Give two physical properties of ionic compounds.

[ 2 ]

All question bank results loaded

Covered syllabus points

2. Atoms, elements and compounds question 1

Question (a)

Question (b)

2. Atoms, elements and compounds question 2

Question (a)

Question (i)

Question (ii)

Question (iii)

Question (iv)

Question (b)

Question (c)

Question (d)

Question (i)

2. Atoms, elements and compounds question 3

Question (a)

Question (b)

Question (i)

Question (ii)

Question (c)

Question (i)

Question (ii)