3.1.4

Atomic Number

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Atomic Number and Mass Number

The atomic number is the number of protons in the atom. The mass number of an atom (or relative mass) is calculated by adding the number of protons and neutrons found in a nucleus. These numbers can be found for each element in the periodic table.

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Sodium

  • Mass number (top) = 23.
  • Atomic number (bottom) = 11.
Illustrative background for CarbonIllustrative background for Carbon ?? "content

Carbon

  • Mass number (top) = 12.
  • Atomic number (bottom) = 6.

Jump to other topics

1States of Matter

2Elements, Compounds & Mixtures

3Atomic Structure

4The Periodic Table

5Chemical Formulae, Equations & Calculations

6Bonding

7Electrolysis

8Groups of the Periodic Table

9The Atmosphere

10Reactivity Series

11Metal Extraction

12Acids & Alkalis

13Chemical Tests

14Physical Chemistry

15Organic Chemistry

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