Summary
Highlights
The periodic table provides valuable information about an element's physical properties. Using carbon as an example, the number above the symbol is the atomic number, indicating the number of protons in an atom's nucleus. Carbon has 6 protons.
In a neutral atom, the number of electrons equals the number of protons to balance their opposite charges. Therefore, a neutral carbon atom also has 6 electrons.
The number below the element's symbol is the atomic mass. Atomic mass primarily depends on protons and neutrons, as electrons have negligible mass. The atomic mass listed on the periodic table (e.g., 12.01 for carbon) is the average of its naturally occurring isotopes.
To find the number of neutrons, subtract the atomic number (number of protons) from the atomic mass (number of protons + neutrons) and round to the nearest whole number. For carbon, 12.01 - 6 = 6.01, which rounds to 6 neutrons.