Isotopes (Cambridge O Level Chemistry)

Protons, neutrons and electrons are subatomic particles.

Complete the table to show the relative mass and relative charge of a proton, a neutron and an electron.

particle	relative mass	relative charge
proton
neutron
electron

[3]

Extended Only

Bromine has two isotopes. 

The table shows the number of protons, neutrons and electrons in some atoms and ions.

Complete the table.

particle	number of protons	number of neutrons	number of electrons
	19	22	18

This question is about elements X, Y and Z.

An atom of element X is represented as 

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

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

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

What is the electronic structure of the ion X^2–?

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

Separate: Chemistry and Extended Only

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, ⁶⁹Y and ⁷¹Y

The ratio of atoms present in element Y is shown.

⁶⁹Y : ⁷¹Y = 3 : 2

• Calculate the relative atomic mass of element Y to one decimal place.

relative atomic mass: ..........

• Identify element Y.   
• element Y: ..........

Element Z is in Period 3 and Group V.

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

Chlorine is in Group VII of the Periodic Table.

Two isotopes of chlorine are chlorine‑35 and chlorine‑37

State why these two isotopes of chlorine have the same chemical properties.

Chlorine is in Group VII of the Periodic Table.

Two isotopes of chlorine are chlorine‑35 and chlorine‑37.

Complete the table to show the number of electrons, neutrons and protons in each atom and ion.

	number of electrons	number of neutrons	number of protons

, and  are isotopes of sodium.

Describe how these sodium isotopes are the same and how they are different in terms of the total number of protons, neutrons and electrons in each.

same:

different:

, and   are isotopes of sodium.

Why do all three isotopes have an overall charge of zero?

This question is about the structures of atoms and ions.

Define the term proton number.

Complete the table to show the number of protons, neutrons and electrons present in atoms of and .

	number of protons	number of neutrons	number of electrons

What term is used to describe atoms of the same element, such as and ?

Extended Only

Explain why the chemical properties of  and  are the same.

Complete the table to identify the atoms and ions which have the following numbers of protons, neutrons and electrons.

	number of protons	number of neutrons	number of electrons
	11	12	10
	4	5	4
	17	20	18

State the electronic structure of the following atom and ion.

Al:

S^2–: