Question

isotope symbol atomic number mass number number of protons number of neutrons

Explanation:

Step1: Identify atomic number

The sub - script in the isotope symbol $_{19}^{40}K$ is the atomic number. So the atomic number is 19.

Step2: Identify mass number

The super - script in the isotope symbol $_{19}^{40}K$ is the mass number. So the mass number is 40.

Step3: Determine number of protons

The number of protons is equal to the atomic number. So the number of protons is 19.

Step4: Calculate number of neutrons

The number of neutrons is calculated by subtracting the number of protons from the mass number. So the number of neutrons is $40 - 19=21$.

Answer:

Property	Value
Mass Number	40
Number of Protons	19
Number of Neutrons	21