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प्रश्न
Differentiate mass number from atomic number.
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उत्तर
| Sr. No. | Atomic number | Mass number |
| 1. | The number of electrons or protons in an atom is called atomic number of that atom. | The number of protons and neutrons present is its nucleus is called 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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| Column A | Column B | ||
| 1. | Mass of proton | a. | +1 |
| 2. | Mass of electron | b. | -1 |
| 3. | Charge of electron | c. | 9.31 x 10-28g |
| 4. | Charge of proton | d. | 1.67 x 10-24g |
