Isotopes & relative atomic mass

This question is about atoms and ions.

The model of the atom has changed over time.

In an early model, scientists thought the atom was a tiny sphere that could not be divided.

Figure 1 represents this early model of the atom.

The discovery of a subatomic particle led to a change in the model in Figure 1.

Which was the first subatomic particle to be discovered?

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In a later model of the atom, most of the mass was concentrated in the centre of the atom.

What is the name of the centre of an atom?

Atoms contain three types of subatomic particle.

Draw one line from each subatomic particle to the relative charge of the particle.

What is meant by the ‘atomic number of an atom’?

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Table 1 shows information about two isotopes of an element.

Calculate the relative atomic mass (A_r) of the element.

Use the equation:

A = (mass number × percentage) of isotope A + (mass number × percentage) of isotope B

Give your answer to 1 decimal place.

An oxygen atom has eight electrons.

Complete Figure 2 to show the electronic structure of an oxygen atom.

Figure 2

Figure 3 represents two models of sodium chloride.

What are two advantages of model B compared with model A ?

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Potassium is in Group 1 of the periodic table.

What name is given to Group 1 elements?

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A potassium atom is very small.

What is the radius of a potassium atom?

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What name is given to the number of protons in an atom?

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Table 1 shows the name and the relative charge of the particles in a potassium atom.

Complete Table 1.

The electronic structure of a potassium atom is 2,8,8,1

Figure 1 represents the electronic structure of a potassium ion.

What is the charge on a potassium ion ?

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Figure 2 shows the melting points of some Group 1 elements.

Predict the melting point of potassium.

Potassium has two isotopes.

Table 2 shows the percentage (%) abundance of the two isotopes.

How is the relative atomic mass (A_r) of potassium calculated?

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Group 7 elements are known as the halogens. All atoms of Group 7 elements contain protons, neutrons and electrons.

What is the order of discovery of the proton, neutron and electron? Tick (✓) one box.

Table 1 shows the mass of a proton and of an electron.

Calculate how many times heavier a proton is than an electron.

A bromine atom can be represented as⁸¹₃₅Br.

What is the number of neutrons in this bromine atom?

What is the number of electrons in a bromide ion ?

Chlorine has two isotopes. Table 2 shows the percentage abundance of the two isotopes of chlorine.

Calculate the relative atomic mass (A_r) of chlorine.

Figure 4 shows the outer shells in one molecule of chlorine (Cl₂). Complete the dot and cross diagram to show the electrons in the outer shells.

This question is about the periodic table.

Figure 11 shows part of Mendeleev’s version of the periodic table.

Which group of elements had not been discovered when Mendeleev’s version of the periodic table was published?

Figure 12 represents different models of the atom.

Which model represents the plum pudding model? Tick (✓) one box.

Which model resulted from Chadwick’s experimental work? Tick (✓) one box.

Potassium has different isotopes.

What is meant by ‘isotopes’? You should refer to subatomic particles.

Table 2 shows the mass numbers and the percentage abundance of two isotopes of potassium.

Calculate the relative atomic mass (A_r) of potassium. Give your answer to 1 decimal place.

This question is about the periodic table.

Figure 1 shows part of Mendeleev’s version of the periodic table.

Which group of elements had not been discovered when Mendeleev’s version of the periodic table was published?

Figure 2 represents different models of the atom.

Which model represents the plum pudding model? Tick (✓) one box.

Which model resulted from Chadwick’s experimental work? Tick (✓) one box.

Potassium has different isotopes.

What is meant by ‘isotopes’? You should refer to subatomic particles.

Table 1 shows the mass numbers and the percentage abundance of two isotopes of potassium.

Calculate the relative atomic mass (A_r) of potassium. Give your answer to 1 decimal place.