How do you find the number of neutrons in an atom
• Use this equation: • Number of Neutrons = Atomic Mass – Atomic Number: • N = M – n where N = Number of Neutrons, M = Atomic Mass, n = Atomic Number • You can find the element in this picture by clicking on it to enlarge Locate your element, for example, osmium, on the periodic table. • Look in the upper left hand corner to find the atomic number. (For osmium, you will see a number 76 there.) That is the number of protons in that element. • Determine the atomic mass by looking underneath the symbol to find the atomic weight. For the example in this article, which is osmium, you’ll find an atomic weight of 190.23. • Round off the atomic weight to the nearest whole number to find the atomic mass. In our example, 190.23 would be rounded to 190, resulting in an atomic mass of 190 for osmium. Subtract the atomic number from the atomic mass. This will give you the calculated number of neutrons in the atom. • N = M – n • 190 total atomic weight – 76 protons = 114 neutrons.
