Final answer:
A neutral sodium atom (22Na) has 11 protons and 11 electrons. To find the number of neutrons, subtract the number of protons (11) from the mass number (22), which reveals that there are 11 neutrons in a sodium atom.
Step-by-step explanation:
The student is asking how many neutrons are in a sodium atom. In standard notation, sodium is represented as 22Na. The atomic number, which is the number of protons, is 11, and since sodium is neutral, it also has 11 electrons. To find the number of neutrons, we subtract the number of protons from the mass number of the sodium atom. The mass number is the sum of protons and neutrons. So for sodium (22Na), with a mass number of 22 and having 11 protons, the number of neutrons is 22 - 11 = 11 neutrons.