Current Atmospheric Composition
Part of Composition of Atmosphere · GCSE GCSE Chemistry revision
This key facts covers Current Atmospheric Composition within Composition of Atmosphere for GCSE Chemistry. Revise Composition of Atmosphere in Atmosphere for GCSE Chemistry with 20 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 4 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 13
Practice
20 questions
Recall
12 flashcards
📊 Current Atmospheric Composition
The atmosphere has been relatively stable for the last 200 million years:
- Nitrogen (N₂) — About 78%. Unreactive gas; released from volcanoes and denitrifying bacteria
- Oxygen (O₂) — About 21%. Produced by photosynthesis; essential for aerobic respiration
- Argon (Ar) — About 0.9%. Noble gas, extremely unreactive
- Carbon dioxide (CO₂) — About 0.04%. Currently increasing due to human activities
- Water vapour — Variable (~1–4%). Depends on temperature and location
Memory key: 78-21-1 = Nitrogen-Oxygen-Argon (NOA)
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Read this section alongside the surrounding pages in Composition of Atmosphere. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Composition of Atmosphere
What is the approximate percentage of nitrogen in the current atmosphere?
Describe how Earth's early atmosphere was formed.
Quick Recall Flashcards
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