Why do elements of transition group begin from 4 period in periodic table???.............?

Answer 1

Because electrons fill the 4s orbital before going into any d orbitals. Which is what makes a transition metal a transition metal. Their valence electrons are in d orbitals.

Answer 2

Elements in the transition group all have similar electron configurations in which the outermost electron is found in the d sublevel of electron shells. This d sublevel doesn't exist, however, until you get to the third energy level. The first and second energy levels don't have a d sublevel because they're too small. It's kind of hard, though, for electrons to be in the d sublevel on the third energy level (denoted 3d) because it's considered a high-energy level. It takes a bit more energy for electrons to be in 3d than it does to be in 4s, the s sublevel on the fourth energy level. So electrons tend to go to the fourth energy level before electrons fill up the d sublevel, which is necessary for an element to be classified as a transitional element.

Answer 3

When medaleve made the periodic table he had only one thing in his mind to group the elements according to their common physical and chemical property. He solved the "zig-saw" any how... and in the process the , that's is why the periodic table is not a perfect rectangular in shape.

Answer 4

because thats the way it is!