Write names and electronic configurations of elements of first period in the modern periodic table. Identify which of them has the stable complete

D) both B and C

C) atomic numbers

Correct option is  A) a, b

The modem periodic table is based on the atomic numbers of the elements. When elements are arranged in an increasing order of atomic number (Z), periodicity is observed in their...

Elements present in the first period i.e., H and He contain only one shell which is also their valence shell and can accommodate maximum two electrons. As first shell can accommodate only...

i. Filling of electrons in the second period: In the second period, electrons are filled in the second shell i.e., n = 2. This shell can accommodate a maximum of eight electrons...

The fourth period corresponds to the filling of fourth shell, n = 4. Therefore, it begins with filling of 4s subshell. The first two elements of the fourth period are K...

i. First period  ii. f-Block

i. 2He: 1s2 Here, n = 1. Therefore, 2He belongs to the 1st period. The shell n = 1 has only one subshell, namely 1s. The outer electronic configuration 1s2 of ‘He’ corresponds to the...

The Modern periodic table removed various anomalies of Mendeleev’s periodic table as follows:  i. All isotopes of the same element have different atomic masses but same atomic number. Therefore, they occupy...