atomic number

Science: Carbon is atomic number 6 on the Periodic Table of Elements.

One of the most critical rare earths is dysprosium, atomic number 66 on the periodic table.

Thus, they exposed the secrets of this extremely rare lanthanide, whose atomic number is 61, in a series of meticulous experiments.

In HAADF-STEM images, signal intensity correlates with the square of the atomic number, making it particularly useful for analyzing heavy elements.

Lighter elements -- generally those with an atomic number of 20 or lower on the periodic table -- often have an equal number of protons and neutrons.