It’s an image almost everyone has seen at some ... The second shell (L) fits eight electrons. Thus the second row of the periodic table contains eight elements, with a gap left between hydrogen ...

Periodic Table (Image source: Freepik ... followed by helium (atomic number 2), and so on. Rows in the periodic table are called periods. Each period signifies a new energy level or electron ...

The modern periodic table is based closely on the ideas he used. Cal: And how is it ordered? Mrs Roberts: So, the elements are arranged in order of increasing atomic number. The horizontal rows ...