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Questions
Differentiate mass number from atomic number.
What is the difference between atomic number and mass number?
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Solution
| Sr. No. | Atomic number | Mass number |
| 1. | The number of electrons or protons in an atom is called the atomic number of that atom. | The number of protons and neutrons present in its nucleus is called the mass number of that atom. |
| 2. | It is represented by the letter Z. | It is represented by the letter ‘A’. |
| 3. | Example: Helium (He) has 2 protons and two electrons; hence, its atomic number will be 2. | Example: Sodium (Na) has 11 protons and 12 neutrons; hence, its mass number A = 11 + 12 = 23 |
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