Homework: Atoms, Elements and Compounds – Levels 4–6
Atmosphere on Mars
In 2004, two space probes landed at different places on Mars. They sent back
information about the atmosphere on Mars.
The tables show some information about the atmosphere on Mars and on Earth.
Atmosphere on Mars
Atmosphere on Earth
Name of gas
Formula
Percentage
Name of gas
Formula
Percentage
carbon
dioxide
CO2
95%
nitrogen
N2
78%
nitrogen
N2
3%
oxygen
O2
21%
other gases
various
2%
other gases
various
1%
The diagram shows how the particles of gas are arranged in the atmosphere on
Earth:
nitrogen
oxygen
Task
Use what you have learnt about atoms, molecules, elements, compounds and
mixtures to:

explain why the atmosphere on Earth and Mars are both mixtures and identify
some differences between the atmosphere on Earth and on Mars

make a table to classify the gases on Earth and Mars into elements and
compounds

explain, using examples from the tables, the difference between an element, a
compound and a mixture

name the elements in carbon dioxide.
Mark Scheme
Level
You should:
4


describe what makes up a mixture of gases
identify at least one difference between the atmosphere on
Earth and Mars.
5

classify the gases as elements and compounds


name the elements in carbon dioxide
explain the meaning of ‘element’ in terms of atoms.


explain the meaning of ‘compound’ in terms of atoms
explain how compounds are different to mixtures

identify at least three differences between the atmosphere
on Earth and on Mars by talking about both the types of gases
and the percentages.
6