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 ...

For example, the atomic number of sodium is 11. Every sodium atom has 11 protons and 11 electrons. It has 11 positive charges and 11 negative charges. Atoms of different elements usually have ...

according to increasing atomic number. 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 ...

The atom with eight protons in its nucleus (atomic number 8) is oxygen. Each energy level holds a ... the next electron goes into the third level. 3rd Period: Sodium to argon—Electrons go into the ...