Describe Thomsons
model
Answers
In Thomson's model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged “plums” surrounded by positively charged “pudding”. The 1904 Thomson model was disproved by Hans Geiger's and Ernest Marsden's 1909 gold foil experiment.
Answer:
(a) J.J Thomson proposed a model of atom that is similar to a water melon.
The electron in the sphere is considered as seeds in watermelon.
He proposed that:
1. Atom consists of a positively charged sphere and the electrons are embedded in it.
2. The negative and positive charges are equal in magnitude so atom is electrically neutral.
This model did not tell us about the presence of neutrons in the atom.
(b) When mass no. is 18 and no. of electrons is 7 then
(i) No. of protons = 7
(ii) No. of neutrons = 18 - 7 = 11
(iii) Atomic no. = 7