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प्रश्न
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]
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उत्तर
Atomic number of
X = 6 = number of electrons (2, 4)
∴ X has 4 electrons in outermost orbit.
Y = 9 = number of electrons (2, 7)
∴ Y form anion = negative ion
Z = 12 = [2, 8, 2]
∴ Z forms cation – positive ion.
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संबंधित प्रश्न
Explain the Atomic 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?
Complete the following table.
| Atomic number | Mass number | Number of Neutrons | Number of protons | Number of electrons | Name of the Atomic species |
| 9 | - | 10 | - | - | - |
| 16 | 32 | - | - | - | Sulphur |
| - | 24 | - | 12 | - | - |
| - | 2 | - | 1 | - | - |
| - | 1 | 0 | 1 | 0 | - |
Dalton said that ______ could not be divided.
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What is the (a) atomic number (b) number of protons in this element?
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Calcium – \[\ce{^40_20Ca}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
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Atomic no. = 1
Mass no. = 1
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Silicon [At. no. = 14, Mass no. = 28]
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- Atomic number = number of protons + number of electrons
- Mass number = number of protons + number of neutrons
- Atomic mass = number of protons = number of neutrons
- Atomic number = number of protons = number of electrons
The Atomic number of an element is 20. It has ______ valence electrons.
