Discovery of Proton

Question 1 Name the positively charged particles present in the atoms of all elements?

Question 2 What is a proton?

Question 3 State relative mass and charge of a proton?

Question 4 Name the scientist who discovered proton?

Question 5 Name the gas which produces anode rays consisting of proton in the discharge tube experiment?

Question 6 How does a proton differ from an electron?

Discovery of Proton

The discovery of cathode rays has shown that all atoms contain negatively charged particles called electrons. Now an atom is electrically neutral, so it must contain some positively charged particles. It has actually been found that all atoms contains positively charged particles called protons.

The protons were discovered by E.Goldstein.

Experimental set up
1)It consist of a long cylindrical tube sealed at both ends and is fitted with two metal electrodes.

2)The electrodes are connected to source of high voltage.

3)The tube is connected to a vaccum pump as to increase or decrease the pressure.

4)The discharge tube is filled with hydrogen gas.

5)He used perforated cathode and it was placed somewhere in the center of the tube.

Experiment
He passed electricity at high voltage and at low pressure through hydrogen gas taken in a discharge tube.

Observation
1)He observed that a stream of heavy particles were given out by the anode(+ve electrode).These stream of particles are called anode rays.

2)Anode rays consist of positively charged particles .

3)These particles are called protons.

Characterstics of Protons
1)The relative mass of proton is 1 u.The absolute mass of a proton is 1.672x 10-24 g.

2)The charge of a proton is equal and opposite to the charge of an electron.The charge of proton is 1.6×10−19 C