Choose the statement (s) that is/are true about alpha emission.

A. Alpha particles are helium nuclei.

B. Alpha particles are negative electrons

C. The emission of an alpha particle results in a daughter element two units less in atomic number and four units less in mass number.

D. The emission of an alpha particle results in a daughter element one unit more in atomic number and the same mass number.

Answer:The statements a and d are correct or true.

Explanation:

Alpha particles are doubly charged helium nucleus (He²⁺) and hence they do not have any electrons as both the electrons present in the He atom are ionized.

Alpha particle is represented by ₂⁴He.

So the alpha particle or doubly charged Helium nucleus only have its available 2 protons along with the 2 neutrons.

So statement a is correct.

An Alpha particles not at all have any electrons so they cannot be negatively charged electrons.

So statement b is incorrect.

Since atomic number of an element = number of protons

mass number = number of protons + number of neutrons,

Since the alpha particle has 2 protons and 4 neutrons and hence any atom which would emit an alpha particle would reduce its atomic number by 2 and mass number by 4.

so statement c is correct.

Also statement d is incorrect.