Atomic Structure | Edexcel GCSE Chemistry Exam Questions 2018

1a1 mark

The diagram shows the particles in the atom of an element.

be-electronic-structure

Particle Y is a proton.

What is particle Z?

☐	A	an electron
☐	B	a molecules
☐	C	a neutron
☐	D	a nucleus

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1b1 mark

Which of these has the smallest mass?

☐	A	an electron
☐	B	a neutron
☐	C	a nucleus
☐	D	a proton

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1c1 mark

What is the mass number of this atom?

☐	A	4
☐	B	5
☐	C	9
☐	D	13

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1d1 mark

What is the atomic number of this atom?

☐	A	4
☐	B	5
☐	C	9
☐	D	13

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1e2 marks

i)

Identify the element that contains this atom.

(1)

ii)

State what is formed when this atom loses its outer shell electrons.

(1)

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2a1 mark

Two different atoms have a different number of neutrons.

The table below shows three statements about the two atoms.

Put a tick (✔) in the box to show which is the correct statement.

The atoms are isotopes
The atoms must be different elements as they have a different number of neutrons
The atoms could be the same element if they also had the same number of protons
The atoms could be the same element if they also had the same number of electrons

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2b1 mark

The relative atomic mass of chlorine is 35.5.

Which is the correct reason why it is not a whole number?

☐	A	chlorine contains half a proton
☐	B	relative atomic mass is the average mass of all of the isotopes of that element
☐	C	relative atomic mass is calculated from the mass of the protons divided by the mass of the neutrons
☐	D	a chlorine molecule has a relative atomic mass of 71, so each atom has a relative atomic mass of 35.5

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2c3 marks

Use words from the box to complete the sentences about chlorine.

protons

atomic

mass

neutrons

relative atomic

35-chlorine has the ................................ number of 35 and the ................................ number of 17. One atom of chlorine has 17 ................................ and electrons.

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2d2 marks

The radius of a nucleus is approximately 10 000 times smaller than the radius of an atom.

Place ticks (✔) in boxes by the two statements about the atom that are correct.

the mass of an atom is concentrated within the nucleus
most of the space of an atom is filled with electrons
most of an atom is empty space
the mass of an atom is evenly distributed throughout the atoms
most of the charge of an atom is concentrated in the nucleus

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3a1 mark

Use the words from the box to complete the sentences about the description of isotopes.

neutrons protons compound element metal

Isotopes are atoms of the same __________ that contain the same number of __________ and electrons but a different number of ____________.

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3b2 marks

Figure 1 shows some statements about the isotopes of carbon-12 (¹²C) and carbon-13 (¹³C).

Put ticks (✓) in the boxes in Figure 1 to show which statements are true and which statements are false

	True	False
Both carbon-12 and carbon-13 have the same number of protons
Carbon-12 has one less electron than carbon-13
Carbon-12 has one less neutron than carbon-13
Both carbon-12 and carbon-13 have the same number of neutrons

Figure 1

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3c1 mark

Isotopes display the same chemical properties.

Put a tick (✓) next to the correct statement that describes why isotopes display the same chemical properties.

Isotopes have the same number of neutrons in the nucleus
Isotopes have the same number of protons in the nucleus
Isotopes have the same number of electrons in their outer shells.

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3d1 mark

J.J. Thomson discovered the electron and proposed a model of the atom known as the “plum pudding” model.

Which statement about the plum pudding model is true?

☐	A	Negative electrons were located in the middle of a spherical cloud of positive charge
☐	B	Negative electrons were spread around the edge of a spherical cloud of positive charge
☐	C	Negative electrons were spread throughout the spherical cloud of positive charge
☐	D	Positive charge was located in the middle of a sphere of negative charge

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2a1 mark

This question is about some of the elements in groups 1 and 2 of the periodic table.

The atomic number of lithium is 3.
The mass number of a lithium atom is 7.

Which row of the table shows the number of protons, neutrons and electrons in an atom of lithium-7?

		Number of protons	Number of neutrons	Number of electons
☐	A	3	3	4
☐	B	3	4	3
☐	C	4	3	7
☐	D	7	4	3

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2b1 mark

Lithium, sodium and potassium are in group 1 of the periodic table.

State, in terms of the electrons in their atoms, what the atoms of lithium, sodium and potassium have in common.

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2c

2 marks

Magnesium has atomic number 12.

Magnesium exists as magnesium-24, magnesium-25 and magnesium-26 atoms.

Explain, in terms of protons and neutrons, why these atoms are isotopes of magnesium.

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2d2 marks

Magnesium and calcium are in group 2 of the periodic table. They are less reactive than the metals in group 1.

Calcium reacts with water to form calcium hydroxide, Ca(OH)₂, and hydrogen, H₂.

Ca (s) + 2H₂O (l) → Ca(OH)₂(s) + H₂(g)

Describe what would be seen when a piece of calcium is dropped into a container of water.

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2e2 marks

Magnesium reacts very slowly with cold water but it reacts faster with steam, H₂O, to form magnesium oxide, MgO, and hydrogen.

Write the balanced equation for the reaction between magnesium and steam.

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2f2 marks

The electronic configurations of magnesium and calcium are

magnesium 2.8.2
calcium 2.8.8.2

When magnesium and calcium react with water they form positive ions.

Suggest an explanation, in terms of their electronic configurations, why calcium is more reactive than magnesium.

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2g

3 marks

A sample of calcium bromide contains 0.2 g calcium and 0.8 g bromine by mass.

Calculate the empirical formula of calcium bromide.
(relative atomic masses: Ca = 40, Br = 80)

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The mass number is 3
The mass number is 7
The atomic number is 3
The atomic number is 7

All the isotopes have 1 proton
All the isotopes have 1 neutrons
One of these isotopes has 3 neutrons
One of these isotopes has 2 electrons

Electrons have a mass of 1 and charge of -1
Electrons have a mass of 0 and charge of +1
Electrons have a mass of 0 and charge of -1
Electrons have a mass of 1 and charge of 0

	Percentage abundance (%)
Magnesium-24	78.7
Magnesium-25	10.1
Magnesium-26	11.2

Atomic Structure (Edexcel GCSE Chemistry)

Exam Questions

Higher Only

☐	A	Number of neutrons = mass number + atomic number
☐	B	Number of neutrons = mass number - atomic number
☐	C	Number of neutrons = mass number x atomic number
☐	D	Number of neutrons = mass number ÷ atomic number

Plum pudding model showed electrons orbiting in shells
Plum pudding model depicted electrons spread throughout a sphere of positive charge
Plum pudding model showed the atom with a nucleus in the center

☐	A	The atom is mainly empty space
☐	B	There are negatively charged electrons orbiting the nucleus
☐	C	There is a concentrated mass of positive charge at the centre of the atom
☐	D	There is an abundance of negative charge at the centre of the atom

☐	A	The mass number of both atoms is the same
☐	B	The atomic number of both atoms is different
☐	C	The atomic and mass number of both atoms is the same
☐	D	The atomic number is the same but the mass number is not the same

☐	A	Protons and neutrons
☐	B	Protons and electrons
☐	C	Neutrons and electrons
☐	D	Protons, neutrons and electrons

☐	A	A nucleus containing protons and neutrons, surrounded by electrons
☐	B	A nucleus containing protons and electrons, surrounded by neutrons
☐	C	A nucleus containing electrons and neutrons, surrounded by protons
☐	D	A nucleus containing protons, surrounded by neutrons and electrons

☐	A	Below 63
☐	B	Between 63.5 and 64
☐	C	Between 64 and 64.5
☐	D	Above 64.5

☐	A	alkali metals
☐	B	fullerenes
☐	C	halogens
☐	D	noble gases