Question

Why is alpha particle calles as an helium nuclei? What is the charge ?

Answer 1

Helium atom has :

2 electrons,

2 protons and

2 neutrons.

In the nucleus, it has 2 protons and 2 neutrons. Alpha-particles has 2 protons and 2 neutrons bound together in a particle. As, its constitution is similar to that of helium nuclei, it is also called helium nucleus.

Since, it has two protons and as neutrons are neutral, it has a +2 charge. Moreover it mass is 4 u.