3 conventions of periodic table...wut are those?

Question

could you help me...wut are the 3 conventions of a periodic table?

Answer 1

The periodic table is based on:

1) increasing # of electrons in the valence shell (across a row)

2) increasing nuclear charge (more rows)

3) inner filling of shells ("expanded" rows)

In addition periodic tables show natural state for: gas, liquid, solid some show artificial elements too.