What is the Position of electron inside Atom ?
Position of electron :-
- In an atom the electrons revolve around the nucleus in definite orbitals. These orbitals were represented by Bohr as K, L, M, N, O or 1, 2, 3, 4, 5. The number of electrons in each orbital is 2n where n is the number of orbitals.
- Accordingly, as per Bohr’s hypothesis, the maximum number of electrons in the outermost shell can be eight.
Orbit | Name of the orbit | No. of electrons |
1 | K | 2×12 = 2 |
2 | L | 2×22 =8 |
3 | M | 2×32 =18 |
4 | N | 2×42 =32 |
5 | O | 2×52 =50 |
- Accordingly, the distribution of electrons in the atoms of the first 20 elements of the periodic table will be as under :
Important Points :-
- The basic particles of atom are electron, proton and neutron.
- The negatively charged particles in the atom are electrons.
- The numeric value of the charge on electron and proton is the same but their sign is opposite.
- James Chadwick discovered neutrons.
- There are 6.022×1023 particles in one mole. This is known as the Avogadro number.
- The NTP volume of 1 mole of a gas is 22.4 litres.
- The formula to determine the maximum number of electrons in a shell is 2n2 .
- When the atomic number is the same but mass number is different they are known as Isotopes.
- Isobars are elements having different atomic number and the same mass number.
- There are three isotopes of hydrogen, Protium, Deutirium and Tritium.
Atomic Structure Important Questions-Answers
1. The Plum Pudding Model of atom was given by:
(a) Neil Bohr
(b) Thomson
(c) Ernest Rutherford
(d) Goldstein
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Answer⇒ { B}
2. The discoverer of neutron was :
(a) C.V. Raman
(b) Rutherford
(c) J.J. Thomson
(d) James Chadwick
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Answer ⇒ { D}
3. The size of atom is :
(a) 10-6 cm
(b) 10-15 cm
(c) 10-2 cm
(d) 10-8 cm
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Answer ⇒ {D }
4. The number of neutrons in the Deutirium Isotope of hydrogen is /are :
(a) one
(b) Two
(c) Three
(d) Not even one
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Answer ⇒ {A }