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प्रश्न
What is the significance of atomic numbers in the modern Periodic Table?
उत्तर १
The chemical and physical properties of all the elements in the modern periodic table are the periodic function of their atomic number, which decides their position in the table.
उत्तर २
- The atomic number of an element is equal to the number of protons in the nucleus. Atomic number is the unique property of an element, because no two elements have the same atomic number.
- Atomic number (Z) = Number of protons and K = Number of electrons.
- Since no two elements have the same atomic number, it distinguishes one element from other elements.
- An element with atomic number 13 will have electronic configurations 2, 8 and 3. This indicates the element's electronic configuration.
- It helps to determine an element's position within the periodic table.
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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 | |
What are the atomic numbers of elements whose outermost electrons is represented by 2p3.
Multiple Choice Questions
The sum of number of protons and number of neutrons present in the nucleus of an atom is called its
The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?
The atom of an element X has 7 electrons in its M shell.
What is the atomic number of element X?
The atomic number of four elements A, B, C and D are 12, 13, 15 and 3 respectively. The element which cannot form a cation is :
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
Which sub-atomic particles in the 3 isotopes of ‘H’ are the same.
Differentiate between the following term:
Atomic number and mass number
What are nucleons? How many nucleons are present in Phosphorous? Draw its structure.
If an atom has 6 electrons in its outermost shell, it is inert.
