law of octave is john newlands arranged the elements in order of their increasing order of atomic masses .it states that whenever the elements are arranged in increasing order of their atomic masses ,the properties of the eight element are a kind of repetition of the first ,just like the notes of music.
The Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.
.Mendeleev's law -Mendeleev also arranged the elements known at the time in order of relative atomic mass, but he did some other things that made his table much more successful. Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table
s block elements are hydrogen,sodium,magnesium,calcium,potassium..etc
the electronic configuration of Mg -2,8,2