Things You'll Need
Instructions
Choose an element to analyze. For example, you may decide to analyze lithium.
Consult a textbook or online listing of the elements and their scientific abbreviations. For example, you can access the National Center for Biotechnology Information website PubChem Compound.
Find or enter the name of the element you want to analyze and discover its scientific abbreviation, or molecular formula (MF). For example, you enter the word "lithium" on the PubChem Compound site and learn that the molecular formula of lithium is Li.
Access a textbook or online periodic table of the elements and find the molecular formula you have identified. For example, you can access the Queen Mary University of London periodic table. You identify the molecular formula Li in the first column of the table, second row from the top.
Read the number in the top left-hand corner or top center of the box designated by the molecular formula you have identified. For example, you read the number 3 at the top center of the box designated Li on the Queen Mary University of London periodic table. This number is the atomic number of lithium.
Note that the atomic number of an element is the number of protons in the nucleus of an atom of that element. For example, there are three protons in the nucleus of an atom of lithium.
Note also that each atom of each element has exactly as many electrons as it has protons. If an atom has seven protons, it will have seven electrons. For example, the atom of lithium you are analyzing has three protons. This atom of lithium must also have three electrons.