OCR Multiple Choice Atomic Structure

Complete the table below to give information about protons, neutrons and electrons.

d

c

b

a

Positive /+

1

Very small 0.0005

Neutral / no charge

Carbon-12 and Carbon 14 are Isotopes?

Which statement describes isotopes?

• Atoms with the same number of protons but a different number of electrons.

• Atoms with the same number of electrons but a different number of protons.

• Atoms with the same number of protons but a different number of neutrons.

• Atoms with the same number of neutrons but a different number of protons.

What is the name of the element?

• Boron

• Beryllium

• Fluorine

• Neon

The charge on an electron is -1.6 x 10^-19 C.

What is the charge on a proton?

• -1.6 x 10¹⁹ C.

• -1.6 x 10^-19 C.

• 1.6 x 10^-19 C.

• 1.6 x 10¹⁹ C.

A potassium isotope can be shown as figure 1.

What are the number of protons, neutrons and electrons in this potassium isotope?

• 19 protons, 19 neutrons, 20 electrons

• 19 protons, 20 neutrons, 19 electrons

• 20 protons, 19 neutrons, 19 electrons

• 20 protons, 20 neutrons, 19 electrons

All elements are made of atoms.

Atoms are made of subatomic particles.

Complete the labels on the diagram of an atom.

a

b

c

Electron

Protons

Neutrons

Look at the table. It shows some information about three atoms.

What is the mass number of atom Z ?

• 3

• 4

• 7

Answer explanation

The mass number is the number of protons and neutrons found in the middle of the atom.

Atoms have no overall charge.

Explain why.

Use ideas about subatomic particles in your answer.

Answer explanation

The atom has equal number of positive protons and negative electrons so the charges are cancelled out.

Look at the information about two isotopes of Carbon.

Explain why these are called isotopes. (2 marks)

Answer explanation

Isotopes have the same number of protons.

A different number of neutrons.

A sodium atom can be shown as:

How many proton, neutrons and electrons are in a sodium atom?

• 11 protons, 12 neutrons, 11 electrons

• 11 protons, 11 neutrons, 12 electrons

• 12 protons, 12 neutrons, 11 electrons

• 12 protons, 11 neutrons, 11 electrons

Answer explanation

The number of protons can be found from the atomic number.

The number of electrons is the same number of protons.

The neutron number is calculated by finding the mass number and subtracting the atomic number.