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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Question 19

This question is about atomic structure and the periodic table. Gallium ( $Ga\text{Ga}$ ) is an element that has several isotopes.

Define the term 'isotopes' by describing the subatomic particles present within these atoms.

[2]

The table below shows the mass numbers and percentage abundances of two isotopes of gallium in a synthetic laboratory sample.

Mass number	Percentage abundance (%)
69	45
71	55

Calculate the relative atomic mass ( $ArA_{\text{r}}$ ) of gallium in this sample. Give your answer to 1 decimal place.

[2]

Gallium ( $Ga\text{Ga}$ ) is in Group 3 of the modern periodic table. Give the numbers of electrons and neutrons in a neutral atom of the isotope $3171Ga^{71}_{31}\text{Ga}$ .

[2]

What is the most likely formula of a gallium ion?

$Ga+\text{Ga}^{+}$
$Ga3+\text{Ga}^{3+}$
$Ga3−\text{Ga}^{3-}$
$Ga2+\text{Ga}^{2+}$

[1]

Gallium was discovered in 1875, several years after Mendeleev published his periodic table. Give two reasons why the discovery and properties of gallium helped Mendeleev's periodic table to become accepted.

[2]

Mass number

Percentage abundance (%)

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

Question 19

Markscheme

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

Question 19

Markscheme

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

Question 19

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

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

Question 19

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