Calculate the electronic configuration of the element.
The number of shells in the electronic configuration of the given element determine it's period i.e. if there are 3 shells in an atom then it will belong to period 3.
The number of valence electrons in the atom determines the group number of that atom i.e. if an element has 4 valence electrons then it must belong to group IV A.
Let us take an example:
Electronic Configuration: 2, 8, 1
Since sodium has 3 shells, it belongs to period 3. Also, we notice that this element has 1 electron in its outermost orbit therefore it belongs to group I A.
Hence, Sodium is present in group IA of period 3 in the modern periodic table.
17 is prodid no.
1) the number of shells will determine the period number .
2) number of Valence Electrons determine the group number .
NOTE : If the valence electrons are more than 2 then 10 needs to be added .
For eg. Boron has 3 valence electrons ( more than 2 ) . Therefore we add 10 .
Giving us 3 + 10 = 13 .
Similarly the group no. of Carbon , Nitrogen will be 14 , 15
can you please tell what are you asking
Explanation:sorry, your questions is wrong. so perfect questions send to me in
period number= number of shells present in an atom
and group number = number of valence electron in the outer most shell for example
Beryllium __ Electronic configuration=2, 2
Fluorine __ Electronic configuration= 2, 7
The atomic number of each element is written above the symbol. A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons.