An element 'X' has its electronic configuration of 'K' shell is (n - 5)s2 and it has total number of electrons in its outermost, penultimate and antipenultimate shell are 2, 8 and 25 respectively, the

Question

An element 'X' has its electronic configuration of 'K' shell is (n - 5)s2 and it has total number of electrons in its outermost, penultimate and antipenultimate shell are 2, 8 and 25 respectively, then find out total number of unpaired electrons in element 'X' in their ground state.

Prashant Kotian · Accepted Answer

Correct answer: 7. Step 1: The d-orbitals only exist starting from the principal quantum number n=3, which means the (n-1)d subshell is first filled when n=4. Step 2: Substitute n=4 into the configuration (n-1)d^6 ns^2 to obtain 3d^6 4s^2. Step 3: This electronic configuration belongs to Iron (Fe, Z=26), which is in the d-block of the fourth period. Thus, the element is located in the fourth period.

💡 Solution & Explanation

Practice 22,000+ questions like this