Advertisements
Advertisements
Question
State how electrons are distributed in an atom. Explain in brief the rules which govern their distribution.
Advertisements
Solution
(a) Electrons revolve around the nucleus in imaginary paths called shells or orbits. Shells start from the nucleus to outwards.
Rules: The maximum number of electrons in a shell is given by 2n2. Where n is the number of shell i.e. 1st shell can have a maximum of 2 electrons.
2n2 = 2(1)2 = 2 × 1 = 2
2nd shell can have maximum of 8 electrons
2n2 = 2(2)2 = 2 × 4 = 8
3rd shell can have maximum of 18 electrons
2n2 = 2 (3)2 = 2 × 9 = 18 and so on….
(b) Outer most orbit cannot have more than 8 electrons and 18 in penultimate orbit.
(c) A new shell cannot start until previous is filled completely.
APPEARS IN
RELATED QUESTIONS
Mention briefly the salient features of Dalton’s atomic theory (five points)
What are the two main parts of which an atom is made of?
FILL IN THE BLANK
In an atom, the last shell containing electrons is called its..................shell.
Tick the most appropriate answer.
How many times is a proton heavier than an electron?
- 1500
- 1800
- 1840
- none of these
WRITE SHORT ANSWER
Describe a discharge tube.
WRITE SHORT ANSWER
What is the number of neutrons present in a potassium atom ?
ANSWER IN DETAIL
Write a note on valence shell.
Compare an electron and a proton in respect of mass and charge.
State the location of electrons, protons and neutrons in an atom.
Name the three fundamental particles of an atom.
