Matching Pairs Periodic Table Vocabulary (D)Online version Use what you learned from your vocabulary flashcards. by Lydia Lawrence 1 Atomic Mass 2 Group 3 Bohr model 4 Neutron 5 Electron 6 Atomic Number 7 Element 8 Proton 9 Period 10 Atom A subatomic particle located in the nucleus with a positive charge. The average mass of the protons plus the neutrons in an atom's nucleus. The number of protons and the number of electrons found in one atom of an element. A vertical column on the periodic table. It is also known as a family. A subatomic particle located in the nucleus with a neutral, or no, charge. The horizontal rows found on a periodic table. A substance made of one type of atom found on the periodic table. These substances make up everything in the universe. A basic visual of a single atom with protons, neutrons, and electrons on energy levels. This model was designed by Neils Bohr. A subatomic particle located on energy levels that has a negative charge. The smallest unit a substance can be divided into and still hold the properties of that substance.