How many `alpha` and `beta` particles will be emitted when `._(90)Th^(234)` change into `._(84)Po^(218)`?

Explanation

The change is :
`underset("Parent")(._(90)Th^(234)) to underset("End parent")(._(84)PO^(218))`
Decrease in mass = (234 - 218) = 16 amu
Mass of 1 `alpha` particles emitted `= (16)/(4) = 4`
Number of `beta` particles emitted
= 2 `xx` No. of `alpha`-particles emitted - (At. No of parent - At no of end product)
`= 2 xx 4 - (90 - 84) = ( 8 - 6) = 2`
Hence, number of `alpha` particles emitted = 4
and number of `beta`-particles emitted = 2