How Do You Find The Number Of Protons, Electrons & Neutrons?
Atoms of chemical elements consist of protons, neutrons and electrons. The number of protons is a distinct feature of a particular element. However, chemical elements typically exist as isotopes that vary in the number of neutrons. The mass number of an isotope refers to the sum of the number of protons and neutrons. Find the element in the Periodic Table of Chemical Elements. For example, chlorine (Cl) is located in the group “VIIA” of the periodic table. Read the atomic number given above the element symbol; this number is equivalent to the number of protons as well as to the number of electrons. The atomic number of chlorine is 17; hence this element has 17 protons and electrons. Navigate to the Isotopic Compositions for All Elements table published at the National Institute of Standards and Technology website. Find the element of interest in the Isotopic composition table. Note that the mass number for each element isotope is given in the third column of the table. In our example,
