Question

5th ques I will mark as brainliest if anyone answers​

Answer 1

In the modern periodic table, atoms with similar electronic configurations are placed in the same column. In a group, the number of valence electrons remains the same. Elements across a period show an increase in the number of valence electrons.

Answer 2

the number of shells in the electronic configuration is equal to the period number of which the element is a part

the number of electrons in the outer most shell is equal to the group number of the element

eg. consider calcium

atomic number=20

period= 4

group=2

electronic configuration=2,8,8,2