The Periodic Table is a well-organized chart that contains all 118 known elements in the universe. These elements are the ...

This is the chemical symbol for chlorine, written with its mass number and atomic number ... in the first shell and one in the second shell. Sodium has 11 electrons. These will be arranged ...

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. The mass number of an atom is its total ...