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प्रश्न
What are orbits or shells of an atom?
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उत्तर
The circular orbits (shell present) in the space available around the nucleus on which electrons revolve are called orbits or shells of an atom.
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संबंधित प्रश्न
Explain the Mass number with example.
The composition of the nuclei of two atomic species X and Y are given as under
| X | Y | |
| Protons | 6 | 6 |
| Neutrons | 6 | 8 |
Give the mass numbers of X and Y. What is the relation between the two species?
Which of the following are isoelectronic species i.e., those having the same number of electrons?
Na+, K+, Mg2+, Ca2+, S2–, Ar
What are the two main features of Rutherford’s atomic model?
What is variable valency? Name two elements having variable valency and state their valencies.
(a) Which of the nuclear particles is present in the same fixed number in the atoms of any particular element?
(b) What do we call this number which is characteristic of a particular element?
Fill in the following blanks in respect of an atom of an element
| No. of protons | No. of neutron | Mass number | Atomic number | No. of electrons | Symbol |
| 11 | 12 | ___________ | ___________ | ___________ | ________ |
Elements X, Y and Z have atomic numbers 6, 9 and 12 respectively. Which one:
- Forms an anion
- Forms a cation
- Has four electrons in its valence shell?
Draw the structure of the following atoms showing the nucleus containing – protons, neutrons and the orbits with the respective electron:
Isotopes of hydrogen [11H, 21H, 31H]
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]
