An element ` ""_(x)A^(y)` emits ` 5 alpha and 4 beta` paricles to give ` ""_(82)B^(207)`. The number of protons and neutrons in A are respectively

Options

A. ` 88,227`
B. 88, 139
C. 82, 227
D. 84, 139

Answer

B

Explanation

`""_(x)A^(y) to ""_(82)B^(207) +5_(2)He^(4) +4""_(-1)beta^(0)`
On comparing ,
` x= 82+5xx2+4(-1)=88`
`y= 207+5xx4+4xx0`
`= 227`
In `""_(88)A^(227)`
the number of protons = 88
the number of neutrons =227-88=139