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

Particle /                          mass number                atomic number

type of radiation

alpha / ⁴₂ He                              4                                     2

beta / e⁰                                     0                                   - 1

gamma / γ                                  0                                     0

neutron / n                                 1                                      0

Explanation:

These are the basic types of radiation: alpha (α), beta (β),  gamma (γ), and neutrons (n).

The radiation is emitted by unstable nuclei when undergo radiactive decay or by nuclei that are shooted by other particles.

Alpha radiation (⁴₂ He):

They are nuclei of helium-4 atoms: 2 protons and 2 neutrons.

Hence, the atomic number, which is the number of protons,  of these particles, is 2; and the mass number, which is the sum of protons and neutrons, is 2 + 2 = 4.

The symbol of this radiation is ⁴₂ He, where the superscript to the left of the chemical symbol is the mass number and the subscript to the left of the chemical symbol is the atomic number.

Beta (⁰₋ ₁ e)

These are electrons emiited from an unstable nucleus. The symbols used for this particle are either ⁰₋ ₁β or ⁰₋ ₁e.

The superscript 0 indicates that the relative mass of this particle is practically zero and the subscript -1 tells that the emission of electrons increases the atomic number of the nucleus that emits it.

Gamma (⁰₀γ)

The gamma rays are electromagnetic radiation of high (the highest) energy.

The both superscript and subscript are zero, meaning that this radiation does not change either the mass or atomic numbers of the nucleus.

Neutron (¹₀n):

Neutrons are also emiited from the nucleus and so they may be considered a radiation.

The atomic number of neutrons is 0 (since it does not have protons) and its mass number is 1.