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प्रश्न
Fill in the blank of the following statement :
All the mass of an atom is concentrated in a small region of space called the ___________.
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उत्तर
All the mass of an atom is concentrated in a small region called the nucleus.
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संबंधित प्रश्न
With the help of given Table, find out the mass number of sulphur atom.
| Composition of Atoms of the First Eighteen Elements with Electron Distribution in Various Shells | ||||||||||
| Name of Element | Symbol | Atomic Number | Number of protons | Number of Neutrons | Number of Electrons | Distribution of Electrons | Valency | |||
| K | L | M | N | |||||||
| Hydrogen | H | 1 | 1 | - | 1 | 1 | - | - | - | 1 |
| Helium | He | 2 | 2 | 2 | 2 | 2 | - | - | - | 0 |
| Lithium | Li | 3 | 3 | 4 | 3 | 2 | 1 | - | - | 1 |
| Beryllium | Be | 4 | 4 | 5 | 4 | 2 | 2 | - | - | 2 |
| Boron | B | 5 | 5 | 6 | 5 | 2 | 3 | - | - | 3 |
| Carbon | C | 6 | 6 | 6 | 6 | 2 | 4 | - | - | 4 |
| Nitrogen | N | 7 | 7 | 7 | 7 | 2 | 5 | - | - | 3 |
| Oxygen | O | 8 | 8 | 8 | 8 | 2 | 6 | - | - | 2 |
| Fluorine | F | 9 | 9 | 10 | 9 | 2 | 7 | - | - | 1 |
| Neon | Ne | 10 | 10 | 10 | 10 | 2 | 8 | - | - | 0 |
| Sodium | Na | 11 | 11 | 12 | 11 | 2 | 8 | 1 | - | 1 |
| Magnesium | Mg | 12 | 12 | 12 | 12 | 2 | 8 | 2 | - | 2 |
| Aluminium | Al | 13 | 13 | 14 | 13 | 2 | 8 | 3 | - | 3 |
| Silicon | Si | 14 | 14 | 14 | 14 | 2 | 8 | 4 | - | 4 |
| Phosphorus | P | 15 | 15 | 16 | 15 | 2 | 8 | 5 | - | 3.5 |
| Sulphur | S | 16 | 16 | 16 | 16 | 2 | 8 | 6 | - | 2 |
| Chlorine | Cl | 17 | 17 | 18 | 17 | 2 | 8 | 7 | - | 1 |
| Argon | Ar | 18 | 18 | 22 | 18 | 2 | 8 | 8 | 0 | |
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?
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.
What is variable valency? Name two elements having variable valency and state their valencies.
Sulphur has an atomic number 16 and a mass of 32.
State the number of protons and neutrons in the nucleus of sulphur. Give a simple diagram to show the arrangement of electrons in an atom of sulphur.
State the main postulates of Dalton’s atomic theory.
State why the atomic weight of an element is also termed relative atomic mass.
Complete the following table.
| Atomic Number | Mass Number | Number of Neutrons | Number of Protons | Number of Electrons | Name of the Element |
| 9 | ______ | 10 | ______ | ______ | ______ |
| 16 | ______ | 16 | ______ | ______ | ______ |
| ______ | 24 | ______ | ______ | 12 | Magnesium |
| ______ | 2 | ______ | 1 | ______ | ______ |
| ______ | 1 | 0 | 1 | 1 | ______ |
Mass No. 27 is for the element ______.
