Given below is a list of chemical species : N ₃^- , I ₃^- , NO ₂^+ , ICl ₂^- , XeF ₂ , CO ₂ The number of species from the above list that have a linear shape AND an expanded octet on the central atom is :

Step-by-step solution

To find the species that are both linear and have an expanded octet (more than 8 electrons around the central atom), we analyze each species: N ₃^- : The structure is [N=N=N]^- . The central nitrogen has 4 bond pairs and 0 lone pairs. Total electrons = 8 (obeys octet). Shape is linear. I ₃^- : The central iodine has 2 bond pairs and 3 lone pairs. Total electrons = 10 (expanded octet). Shape is linear. NO ₂^+ : The structure is [O=N=O]^+ . The central nitrogen has 4 bond pairs and 0 lone pairs. Total electrons = 8 (