Question

question 4 (1 point)
how many neutrons are on potassium - 40?
¿cuántos neutrones hay en el potasio - 40? (6d)
○ a 19
○ b 20
○ c 21
○ d 22

Explanation:

Step1: Recall the formula for neutrons

The formula for the number of neutrons \(N\) is \(N = A - Z\), where \(A\) is the mass number and \(Z\) is the atomic number.

Step2: Identify \(A\) and \(Z\) for potassium

For potassium - 40, \(A = 40\) (mass number). The atomic number of potassium \(Z=19\) (from the periodic table).

Step3: Calculate the number of neutrons

Substitute \(A = 40\) and \(Z = 19\) into the formula \(N=A - Z\). So \(N=40 - 19=21\).

Answer:

C. 21