Question

Question
Potassium’s atomic number is 19, and its atomic mass is approximately 39. How many neutrons does potassium have?(2 points)
Responses

20
20

19
19

39
39

58

Answer 1

To find the number of neutrons in an atom, you can use the formula:

\[
\text{Number of neutrons} = \text{Atomic mass} - \text{Atomic number}
\]

For potassium (K), the atomic number is 19 and the atomic mass is approximately 39.

So:

\[
\text{Number of neutrons} = 39 - 19 = 20
\]

Thus, potassium has **20 neutrons**.