What is periodic in the periodic table?
The modern periodic table is modified form of the mossleys periodic table,which was yet modifiied form of the mendileevs periodic table,which was based on the principle-atomic mass is the periodic function of the elements.Mossley changed the periodicity of elements to be the periodic functions of their atomic numbers.hence in the modern periodic table we can find,the repeatation of certain properties of elements after definite intervals and hence the periodic table has groups and periods the elements inside which,are similar.this is possible because across a period electrons increase by 1,keeping shells sama,and down a group,outer electrons remain same,but shells increase by1.
