STUDENT SPACE · TOPIC 1
Atoms and elements
Distinguish an element from a compound and describe the structure of an atom.
The essentials
- An element contains one type of atom. A compound contains different elements chemically combined in a fixed ratio.
- Protons and neutrons are in the nucleus; electrons occupy shells around it.
- A neutral atom has equal numbers of protons and electrons.
Key vocabulary
| English | Chinese |
|---|---|
| atom | 原子 |
| element | 元素 |
| nucleus | 原子核 |
| electron | 电子 |
Quick practice
A molecule contains two nitrogen atoms. Is it an element or a compound?
Need a hint?
Count the types of atoms, not just the number of atoms.
Check your reasoning after trying
It is an element because it contains only nitrogen atoms. Two atoms do not necessarily mean two different elements.
Use the matching chapter worksheet. Attempt independently, compare your reasoning with your partner, then bring unresolved questions to your teacher.
Isotopes and Atomic Mass
Change the number of neutrons and compare isotope mixtures.
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