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प्रश्न
Explain the Atomic number with example.
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उत्तर
- The number of protons present in the nucleus of an atom is called atomic number.
- It is denoted by Z.
- e.g., in `""_20^40Ca,` atomic number = 20
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संबंधित प्रश्न
If number of electrons in an atom is 8 and number of protons is also 8, then
- What is the atomic number of the atom? and
- What is the charge on the atom?
Multiple Choice Questions
The sum of number of protons and number of neutrons present in the nucleus of an atom is called its
(a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example.
(b) What is the relation between the atomic number and mass number of an element?
(c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
What is meant by the 'atomic number of an element'?
Match the statements in List I with the correct answer from List II.
| List I | List II |
| 1. Mass number of an atom is the number of protons and | A: Electron |
| 2. The sub-atomic particle with a negligible mass. | B: Argon |
| 3. An atom having stable electronic configuration. | C: Nitrogen |
| 4. A molecule formed by sharing of electrons [covalency] | D: Sodium |
| 5. A metallic atom having unstable electronic configuration. | E: Neutrons |
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
Are isotopes atoms of the same element or different elements.
From the symbol \[\ce{^4_2He}\] for the element helium, write down the mass number and the atomic number of the element.
Elements X, Y, Z have atomic numbers 6, 9 and 12 respectively. Which one:
- forms anion – negative ion;
- forms cation – positive ion;
- has 4 electrons in the outermost orbit. [Y, Z, X]
If element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
An element has 2 electrons in its N shell.
What is its atomic number?
