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प्रश्न
Differentiate between the following term:
Atomic number and mass number
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उत्तर
Differentiate between:
Atomic number:
- Z is the number of protons or the number of electrons in an atom.
- Present in nucleus = P
Present in orbits = e
Mass number:
- A is the sum of protons and neutrons.
- Present in the nucleus of an atom.
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संबंधित प्रश्न
Explain the Mass number with example.
In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is - 1.282 × 10-18C, calculate the number of electrons present on it.
Multiple Choice Questions
The sub atomic particle with negative charge is
Fill in the following blanks :
| Atomic Number | Mass Number | Protons | Neutrons | Electrons | Symbol |
| 10 | 22 | _________ | _________ | _________ | _________ |
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Argon – \[\ce{^40_18Ar}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
‘Valency is the number of hydrogen atoms which can combine with [or displace] one atom of the element [or radical] forming a compound’. With reference to the above definition of valency, state the valency of chlorine in hydrogen chloride, giving reasons.
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
If an isotope of ‘H’ has mass no. = 3, how many neutrons does it have.
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]
In a neutral atom number of protons is equal to the number of neutrons.
