Question

Figure 2.3 How many neutrons do (K) potassium-39 and potassium- 40 have, respectively?

Short answer

Answer: Potassium-39 (K-39) has 20 neutrons, and potassium-40 (K-40) has 21 neutrons.

Step-by-step solution

Identify the atomic number of potassium (K)

The atomic number of potassium (K) is 19. This means every potassium atom has 19 protons.

Identify the mass numbers for the isotopes

The mass numbers for the potassium isotopes are given as 39 for potassium-39 (K-39) and 40 for potassium-40 (K-40). The mass number represents the sum of the number of protons and neutrons in the nucleus of an atom.

Calculate the number of neutrons in potassium-39 (K-39)

To find the number of neutrons in potassium-39 (K-39), we need to subtract the atomic number (number of protons) from the mass number. This can be done using the following formula: Number of neutrons = Mass number - Atomic number In the case of potassium-39 (K-39), Number of neutrons = 39 - 19 = 20 There are 20 neutrons in potassium-39 (K-39).

Calculate the number of neutrons in potassium-40 (K-40)

Similarly, we'll calculate the number of neutrons in potassium-40 (K-40) using the same formula: Number of neutrons = Mass number - Atomic number In the case of potassium-40 (K-40), Number of neutrons = 40 - 19 = 21 There are 21 neutrons in potassium-40 (K-40).

Conclusion

Potassium-39 (K-39) has 20 neutrons, and potassium-40 (K-40) has 21 neutrons, respectively.