To determine the number of protons, neutrons, and electrons for an atom, you need to know its atomic number and mass number. Here's how you can find each component:
Protons: The atomic number of an element represents the number of protons in the nucleus of its atom. Therefore, the atomic number itself gives you the number of protons. For example, the atomic number of carbon (C) is 6, indicating that a carbon atom has 6 protons.
Neutrons: The mass number of an atom represents the total number of protons and neutrons in its nucleus. To find the number of neutrons, subtract the atomic number (number of protons) from the mass number. The difference between the mass number and atomic number gives you the number of neutrons. For instance, carbon has a mass number of 12.011 (rounded to 12), and since it has 6 protons (atomic number), the number of neutrons is 12 - 6 = 6.
Electrons: In a neutral atom, the number of electrons is equal to the number of protons. So, you can determine the number of electrons by using the atomic number. For example, since carbon (C) has 6 protons, it also has 6 electrons when it is neutral.
It's important to note that the number of protons and electrons remains the same in a neutral atom, but the number of neutrons may vary among different isotopes of the same element.