There are 118 elements in the periodic table, each with a unique symbol and atomic number. Symbol: A one or two-letter abbreviation used to represent the element. Atomic number: The number of ...

Scientists use the periodic table to quickly refer to information about an element, like atomic mass and chemical symbol. The periodic table’s arrangement also allows scientists to discern trends in ...

This symbol shows that chlorine has ... The relative charge of a nucleus is the same as its proton (atomic) number. Key fact: isotopes are forms of an element that have the same number of protons ...