Question

for iodine - 131 with a chemical symbol and net charge of i - what is the number of neutrons
44
22
10
25
56
78
13
40
100
12
131
54
11
53

Explanation:

Step1: Recall atomic number of iodine

The atomic number of iodine (I) is 53.

Step2: Recall mass - number concept

The mass - number of iodine - 131 is 131.

Step3: Use formula for number of neutrons

The formula for the number of neutrons $n$ is $n = \text{Mass number}-\text{Atomic number}$. So, $n=131 - 53$.
$n = 78$

Answer:

78