Atomic Structure (Edexcel GCSE Chemistry)

The atomic structure of an unknown element is shown below. 

What is the atomic number and mass number for the unknown element?

Atoms contain electrons, neutrons and protons.

i) Draw one line to link each particle to its correct relative charge. (2)

ii) Which of the following is the relative mass of a proton?

(1)

A 0
B
C 1 
D -1

Argon is in group 0 of the periodic table. Identify, using the periodic table, which of these elements is in the same period as argon.

Figure 4 shows the atomic number and mass number of two isotopes of argon.

Figure 4

Describe the structure of an atom of argon-38 and of an atom of argon-40.

As the atomic model developed, protons, neutrons and electrons were discovered. 

What was the correct order of discovery?

Chlorine has an atomic number of 17.

Figure 3 shows the arrangement of electrons in an atom of chlorine.

Figure 3

i) What is the electronic configuration of this atom?

(1)

ii) Explain, using Figure 3, why chlorine belongs to group 7 of the periodic table.

(2)

The nucleus of an atom is made up of protons and neutrons. Atoms of chlorine contain 17 protons.

Figure 4 shows some information about a proton, a neutron and an electron.

Figure 4

i) Explain, using the information in Figure 3 and Figure 4, why atoms of chlorine have no overall charge.

(2)

ii) Atoms of chlorine-37 have a mass number of 37. Calculate the number of neutrons in atoms of chlorine-37.

(1)

number of neutrons = .................................................

iii) There are two isotopes of chlorine, chlorine-35 and chlorine-37. Explain the meaning of the term isotopes.

(2)

Chlorine–35 and chlorine–37 are isotopes. 

Which statement describes an isotope?

Higher Tier Only 

Titanium and iron are examples of transition metals.

Figure 6 shows the percentage abundance of each isotope in a sample of titanium.

Figure 6

Calculate the relative atomic mass of titanium in this sample.

relative atomic mass = ......................................

Iron, when heated in air, reacts with oxygen to form iron oxide.

i) This reaction is an example of (1)

ii) The equipment shown in Figure 7 can be used to find the mass of oxygen that combines with iron.

Figure 7

Describe how the equipment shown in Figure 7 could be used to find the mass of oxygen that combines with 0.500 g of iron wool in a crucible and lid of known mass.

(3)

2.24 g of iron combines with 0.96 g of oxygen to form an oxide of iron.

Determine the formula of this oxide of iron and use it to complete the balanced equation.

(relative atomic masses: Fe = 56.0, O = 16.0)

You must show your working.

balanced equation for the reaction is

................ Fe + ................O₂ → ................................................

Rutherford’s gold foil experiment led to the development of a different model of the atom.

Describe Rutherford’s model of the atom.

Atoms contain protons, neutrons and electrons. Their masses and charges are compared to each other and are known as relative atomic masses and relative atomic charges.

Complete the table to show the correct relative atomic masses and charges.  

Explain why atoms have a neutral charge. 

In terms of subatomic particles, compare the isotopes of carbon shown in the diagram below.

The atomic model developed by scientists has changed over time as experimental evidence improved understanding.

Explain how Niels Bohr contributed to the atomic model. 

Compare the relative atomic masses and relative atomic charges of the subatomic particles within an atom. 

Higher Tier Only

Figure 1 shows the percentage abundance of two isotopes of chlorine.

Figure 1

Calculate the relative atomic mass of chlorine. 

Explain why carbon-12 and carbon-13 are isotopes of the same element.

Give your answer in terms of subatomic particles. 

Compare J.J. Thomson’s plum pudding model with Rutherford’s nuclear model of the atom. 

Explain what isotopes are. 

Explain how the gold foil experiment led to a better understanding of the nucleus. 

Explain how the characteristics of subatomic particles within an atom contribute to the overall charge and mass of an atom. 

Explain the impact of the discoveries of the electrons, nucleus and neutron on the evolution of the atomic model. 

Higher Tier Only

Explain how the relative atomic mass of an element is calculated and use the example in figure 1 to illustrate your explanation. 

Figure 1

Explain the relationship between mass number and atomic number in determining the identity and properties of an element. Use carbon-12 and carbon-13 as an example. 

Explain the structure of an atom according to the current atomic model. 

Bohr further developed the atomic model proposed by Rutherford.

Compare the main features of Bohr’s improvement to the atomic model.

Rutherford’s model of the atom improved the understanding of the atom. Explain how older models were limited in their understanding of the atom. 

Explain why isotopes of an element will have similar chemical properties.

Explain why an atom does not collapse inwards.