Question

An isotope of sodium (Na) has a mass number of \(22 .\) How many neutrons does it have? a. 11 b. 12 c. 22 d. 44

Short answer

Answer: a. 11

Step-by-step solution

Find the atomic number of sodium

Look up the atomic number of sodium (Na) in the periodic table. The atomic number of sodium (Na) is 11, which means it has 11 protons.

Use the mass number to find the number of neutrons

The given mass number of the sodium isotope is 22. Since the mass number is the sum of the number of protons and neutrons, we can find the number of neutrons by subtracting the atomic number (number of protons) from the mass number: Number of neutrons = Mass number - Atomic number

Calculate the number of neutrons for the sodium isotope

Now, we have all the information to calculate the number of neutrons in the sodium isotope: Number of neutrons = 22 (mass number) - 11 (atomic number) Number of neutrons = 11 The sodium isotope with a mass number of 22 has 11 neutrons. So the correct answer is: a. 11