History of the atom

Question 1

what did Democritus propose and in what year

Answer 1

in 440bc, democritus theorised that everything is made up of identical lump called atomos

Question 2

what did Dalton propose and in what year

Answer 2

in 1807, dalton theorised that matter is made of tiny spheres that can’t be created or destroyed

Question 3

what did jj thompson propose and in what year

Answer 3

in 1897, dalton Discovered the electron, and thought that atoms are spheres of mpositive charge with tiny negative electrons stuck in them, known as the plum pudding model.

Question 4

what did rutherfood propse and in what year

Answer 4

in 1908, rutherfood discovered the nucleus, which is positively charged and where most of the mass is concentrated.

Question 5

what did bohr propose and in what year

Answer 5

in 1913, bohr “Electrons orbit the nucleus at different energy levels.”

Question 6

what did chadwick and in what year

Answer 6

in 1932, chadwick discovered the neutron

Question 7

Jj Thompson created the plum pudding model what was it ?

Answer 7

He discovered the electron. Compared to a plum pudding. Discovered the electron, and thought that atoms are spheres of positive charge with tiny negative electrons stuck in them, known as the plum pudding model.Ball of
positive charge with negative electrons in it (the pudding)

Question 8

Rutherford discoverd tje nucleus what happened in the experiment

Question 9

what were the three observation of rutherfoods experiment

Answer 9

1. most alpha particcles go straight through
   2.a few alpha particles deflected through a large angle #
2. a small number of particles deflected

Question 10

what were the reasos for those observationd

Answer 10

3..therfore the nucleus must be very small
1.therefore most of the atoms are empty space
2.