A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

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Question 43
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This question is about atomic structure and the periodic table.

Gallium (Ga) is an element that has several isotopes.

a.

Give the meaning of 'isotopes'.

You should answer in terms of subatomic particles.

[2]
b.

Table 1 shows the mass numbers and percentage abundances of two isotopes in a sample of gallium.

Table 1

Mass numberPercentage abundance (%)
6962
7138

Calculate the relative atomic mass (ArA_rAr​) of gallium in this sample.

Give your answer to 1 decimal place.

[2]
c.

Gallium (Ga\text{Ga}Ga) is in Group 3 of the modern periodic table.

Give the numbers of electrons and neutrons in an atom of the isotope 3171Ga{}^{71}_{31}\text{Ga}3171​Ga.

[2]
d.

What is the most likely formula of a gallium ion?

Select one option:

  • Ga+\text{Ga}^{+}Ga+
  • Ga3+\text{Ga}^{3+}Ga3+
  • Ga3−\text{Ga}^{3-}Ga3−
  • Ga5+\text{Ga}^{5+}Ga5+
[1]
e.

Gallium was discovered 6 years after Mendeleev published his periodic table.

Give two reasons why the discovery of gallium helped Mendeleev's periodic table to become accepted.

[2]

A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes Questions

  1. GCSE
  2. /Chemistry
  3. /A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes