Question

An element X has atomic number 94 and mass number 242 emits two alpha particle.What will be the atomic number and mass number of new element formed?

Answer 1

Dear student

An alpha particle is ⁴He₂, [ a helium nucleus] , which reduces mass by 4 units and atomic number by 2 units.
Here there are two alpha particles getting released, so [ 8 units will be lost from the mass number and 4 units from the atomic number]
the equation becomes :
${}_{94}{}^{242}X\stackrel{-2{}_2{}^{4}He}{\to }{}_{90}{}^{234}Y$
The mass number of the new element is thus 234. and atomic number is 90.