AQA Revision Notes - C2

Subatomic Particles

• Atoms have a small central nucleus made up of protons and neutrons.
• Nucleus surrounded by electrons.
• Protons have a positive charge [+1].
• Electrons have a negative charge [-1].
• Atoms of different elements have different numbers of protons (also known as atomic number).
• Atomic number is the number of protons.
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