how many neutrons are in an atom represented by $_{88}^{220}ra$? 308 13…

$how many neutrons are in an atom represented by $_{88}^{220}ra$? 308 13…$

how many neutrons are in an atom represented by $_{88}^{220}ra$?
308
132
220
88

The notation $_{88}^{220}\text{Ra}$ has mass number $A = 220$ and atomic number $Z=88$.

The number of neutrons $N$ is given by $N=A - Z$.
Substitute $A = 220$ and $Z = 88$ into the formula: $N=220 - 88$.
$N = 132$.

B. 132