The first (with H and He at the top) is known as the ‘s’ block, the second (with B to Ne at the top) is known as the ‘p’ block, the third (the transition metals, in the middle) are known as the ‘d’ block, and the lanthanide and actinide series are known as the ‘f’ block.

To simplify things, imagine the nucleus as the sun, and then the electrons orbiting around it. The blocks refer to the orbit ‘shape’ (a simplification, but it will do), and the number of electrons that can fit in the orbit depends on the block (‘s’ orbits can hold 2 electrons, ‘p’ can hold 6, ‘d’ can hold 10 and ‘f’ can hold 14).

As you work your way along the rows of the periodic table, the number of electrons ( the atomic number) increases by one, so H has 1 electron, He has 2 etc…

if you look “periodic table” up on wikipedia, its all spelled out for you. good luck.

and although i dont feel as if i should help you…ill do it anyway…the numbers increase with the incresaing mumber of electrons in each molecule