Proton – Mass and Charge of Proton

Proton – Mass and Charge of Proton

Charge of proton depends upon the number of electron and proton it contains. In this topic, we will teach you about mas and charge of a proton.

Around 500BC an Indian philosopher, Maharishi Kanad said that if we go on dividing the matter we shall get smaller particles. He named it Parmanu. Later on a Greek philosopher, Democritus suggests that on dividing a matter we can obtain an indivisible particle, which is indivisible.

Furthermore, he pronounces it an atom. With further experiments, scientists came to know that atoms are further made up of three subatomic particles, electrons, protons and neutrons. The charge of proton is positive while electrons have a negatively charge whereas neutrons have no charge.

Discovery of Subatomic Particles

A model for the structure of an atom was first proposed by J. J. Thomson. We call it Thomson’s pudding model. Thus, the cathode ray tube experiment of Thomson led to the discovery of electrons. In 1932, James Chadwick discovered another subatomic particle, neutrons. In 1886, E. Goldstein discovered protons with the help of anode ray experiment. We represent Electrons as ‘e−’, protons as ‘p+’, and neutrons as ‘n’.

Anode Ray Experiment and Discovery of Protons

Protons were discovered by the anode ray experiment which was conducted by E. Goldstein way back in 1886. We also call these anode rays as canal rays. Some important points of the experiment are as follows:-

– He takes a gas-filled tube with positive and negative electrodes on two sides.

– He makes the cathode plate porous and applies a layer of zinc sulphide on it.

– Later, A high voltage current of about 10kv was allowed to pass through the tube.

– When the atmospheric pressure was gradually decreased below 1 atm a gas illumination was seen at the back of the cathode plate.

– The rays contain positively charged particles as they repel towards the cathode plate.

-Layer on Rutherford name these positively charged particles as ‘protons’.

Atomic Structure and Position of Protons

J. J. Thomson’s model was rejected as it failed to determine the exact position of subatomic particles. Interestingly, Thomson’s model later led E. Rutherford to design the gold foil experiment. This experiment ultimately led to the discovery of the atomic nucleus. After Neil Bohr’s atomic model it became easier to position the electrons, protons, and neutrons. Besides, the protons and neutrons are present in a small nucleus at the center of the atom. Electrons are present outside the nucleus in a fixed orbit that we know as a shell.

Properties of Protons

The positive charge of protons makes the nucleus also positive. We consider an atom as neutral because it has the same number of protons and electrons. The absolute mass of a proton is 1.6726 x 10-27 kg. Its absolute charge is 1.6022 x 10-19 coulomb of a positive charge.

Besides, the atomic number is the number of protons present in one atom of that element. Thus, in the periodic table, we arrange the elements according to their atomic number. A strong nucleic force binds protons and neutrons together.

The combined mass of proton and neutron virtually makes the mass of an atom. Unlike electrons, protons do not take part in a chemical reaction.

Solved Question for You

Q. How do protons determine the charge of an atom?

Ans. Charge of an atom completely depends on the number of protons in an atom. If the number of protons is more than electrons in an atom, it becomes cationic.

Whereas the less number of protons than electrons makes the atom anionic. Elements having more protons are metals while the fewer protons elements are the non-metals.