The table below shows the approximate percentages of carbon dioxide, nitrogen, and oxygen in the Earth's early atmosphere compared to today's atmosphere.
| Gas | Approximate percentage in the early atmosphere | Percentage in today's atmosphere |
|---|---|---|
| Carbon dioxide | 95% | 0.04% |
| Nitrogen | 4% | 78% |
| Oxygen | 0% | 21% |
Over billions of years, natural processes have significantly changed the percentages of these gases.
Explain how the percentage of each of these three gases in the atmosphere changed to reach their current levels.
Practise Edexcel GCSE Chemistry Earth and atmospheric science with exam-style questions for Foundation and Higher tier. 62 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
