Question

Fill in the missing mass number and atomic number for each of these particles or types of radiation.

alpha (?) He
beta (?) e
gamma y
neutron n

Answer 1

Concepts and reason

The relative mass and the charge of particle such as a proton, an electron, a nucleon or a nucleus is described by a notation as follows:

$_Z^A{\rm{X}}$

Here, A is the relative atomic mass, and Z is the charge over a species denoted by symbol X.

Fundamentals

A substance is said to be a part of matter if, it is having a certain amount of mass, volume and occupy some space. For example, helium molecule.

Radiation is a form of energy (electro-magnetic) having no mass and is intangible. It does not require a medium for its transmission. For example, gamma ray.

Several species are there which shows behaviour of being as matter and of radiation energy. For example, an electron.

A

An alpha particle is a name used for the helium atom.

A helium atom has 2 protons and 2 neutrons in its nucleus.

The notation for alpha particle is as follows:

$_2^4{\rm{He}}$

B

A beta particle is a synonym used for an electron.

An electron is a species having a unit negative charge.

The notation for the beta particle is $_{ - 1}^0{\rm{\beta }}$ .

C

A gamma particle is a form of energy that shows only the wave like behaviour.

Gamma particles are highly intense radiations with a huge penetrating power.

They are intangible and can be detected with special types of instruments.

The notation for the gamma ray is $_0^0\gamma$ .

D

A neutron is a subatomic particle found in the nucleus of an atom or as a free particle in nuclear reactions.

The important property of a neutron is that, it has a similar mass as that of a proton.

But, the charge content is neither positive or a negative.

The notation for the neutron is $_0^1{\rm{n}}$ .

Ans: Part A

The symbol for the alpha particle is $_2^4{\rm{He}}$ .

Part B

The symbol for the beta particle is $_{ - 1}^0{\rm{\beta }}$ .

Part C

The symbol for the gamma ray is $_0^0\gamma$ .

Part D

The symbol for the neutron is $_0^1{\rm{n}}$ .