AP EAPCET 19-Aug-2021 Shift 2 Paper

For electronic configuration =(n−1)d2ns2 Sum of electrons present in outer most orbital (d and s ) denoted group and period position is represented by principal quantum number.
e.g. (n−1)d2ns2 Group = number of valence electrons in d and s-orbital.
Sum of electrons in d and s orbital =2+2=4
∴ Number of electrons in d-orbital and valence shell =4
∴ 4th group and 4th period.