- Identify the Element: The element with atomic number 16 is Sulphur (S).
- Identify the Molecule: The question refers to its paramagnetic diatomic form, which is S2 (typically found in the vapour phase at high temperatures).
- Determine Valence Electrons: Sulphur belongs to Group 16 (like Oxygen). Electronic configuration: [Ne]3s23p4. Each sulphur atom contributes 6 valence electrons. Total valence electrons in S2=6+6=12.
- Apply Molecular Orbital Theory (MOT): The filling order for valence electrons (analogous to O2) is:
σ3s2<σ3s∗2<σ3pz2<(π3px2=π3py2)<(π3px∗1=π3py∗1)
- Count Unpaired Electrons: The last 2 electrons occupy the two degenerate antibonding π∗ orbitals singly (following Hund's Rule). Thus, there are 2 unpaired electrons.
(Note: While the specific properties of S2 are covered in the p-Block elements chapter, the principles of paramagnetism and unpaired electrons are detailed in the provided Class 12 Chemistry source, Unit 4 and 5, and the methodology derives from general Chemical Bonding.)