Notes : Proton: Definition, Discovery and Properties - Param Himalaya

Proton: Definition, Discovery and Properties

Definition of Proton

A proton is a positively charged subatomic particle present in the nucleus of every atom. It carries one unit of positive charge and, together with neutrons, forms the nucleus of an atom.

Symbol: $p$ or $^1_1H$

Charge: $+1.602 \times 10^{-19}\ \text{C}$

Mass: $1.6726 \times 10^{-27}\ \text{kg}$

Relative Mass: $\approx 1\ \text{a.m.u.}$

Discovery of Proton

The proton was discovered by Ernest Rutherford in 1917 during his experiments on the bombardment of nitrogen gas with alpha particles.

Rutherford's Experiment

Rutherford bombarded nitrogen nuclei with high-speed alpha particles. He observed the emission of hydrogen nuclei, which were positively charged particles.

Nuclear Reaction:

$^{14}_{7}N + ^{4}_{2}He \rightarrow ^{17}_{8}O + ^{1}_{1}H$

or

${}^{14}_{7}\mathrm{N}+{}^{4}_{2}\mathrm{He}\rightarrow{}^{17}_{8}\mathrm{O}+{}^{1}_{1}\mathrm{H}$

From this experiment, Rutherford concluded that the hydrogen nucleus is a fundamental constituent of atomic nuclei and named it the proton.

Properties of Proton

1. A proton carries a positive charge of

$+1.602 \times 10^{-19}\ \text{C}$

2. It is located in the nucleus of an atom.

3. The mass of a proton is

$1.6726 \times 10^{-27}\ \text{kg}$

4. The mass of a proton is approximately 1836 times the mass of an electron.

5. The number of protons in an atom determines its atomic number ($Z$).

6. Protons are stable particles and do not decay under normal conditions.

7. Along with neutrons, protons contribute to the mass of the nucleus.

8. All atoms of the same element contain the same number of protons.

Conclusion: 

A proton is a positively charged particle present in the nucleus of an atom. It was discovered by Ernest Rutherford in 1917 through the bombardment of nitrogen nuclei with alpha particles. The proton has a charge of $+1.602 \times 10^{-19}\ \text{C}$ and a mass of $1.6726 \times 10^{-27}\ \text{kg}$. The number of protons in an atom determines the identity and atomic number of an element.

Frequently Asked Questions (FAQs) About Proton

What is a proton?

A proton is a positively charged subatomic particle present in the nucleus of an atom. It carries a charge of +1.602 × 10^-19 C and has a mass of approximately 1 a.m.u.

Who discovered the proton?

The proton was discovered by Ernest Rutherford in 1917 during his experiments involving the bombardment of nitrogen nuclei with alpha particles.

How was the proton discovered?

Rutherford bombarded nitrogen nuclei with alpha particles and observed the emission of hydrogen nuclei. He identified these hydrogen nuclei as fundamental positively charged particles called protons.

What is the nuclear reaction involved in the discovery of the proton?

The nuclear reaction observed by Rutherford was:

$^{14}_{7}N + ^{4}_{2}He \rightarrow  ^{17}_{8}O + ^{1}_{1}H$

What is the charge of a proton?

The charge of a proton is +1.602 × 10^-19 coulomb.

What is the mass of a proton?

The mass of a proton is 1.6726 × 10^-27 kg, which is approximately equal to 1 atomic mass unit (a.m.u.).

Where are protons found?

Protons are found in the nucleus of an atom along with neutrons.

What is the symbol of a proton?

The symbol of a proton is p or ¹₁H.

Why are protons important?

Protons determine the atomic number and identity of an element. Different elements have different numbers of protons.

What are the main properties of a proton?

The main properties of a proton are positive charge, mass of approximately 1 a.m.u., location in the nucleus, and its role in determining the atomic number of an element.