Sodium had an atomic mass of 23 and an atomic number of 11. How many neutrons does phosphorous have?
Group of answer choices
0
11
12
23
The atomic number of an element represents the number of protons it has. Since sodium has an atomic number of 11, it means there are 11 protons in its nucleus.
The atomic mass of an element represents the sum of protons and neutrons in its nucleus. For sodium, the atomic mass is 23, which means there must be 23 - 11 = 12 neutrons in its nucleus.
Therefore, phosphorus would have 12 neutrons. So, the correct answer is 12.