The number of species from the following which are paramagnetic and with bond order equal to one is mathrm H_2, mathrmHe_2^+, mathrmO_2^+, mathrmN_2^2-, mathrmO_2^2-, mathrmF_2, mathrmNe_2^+, mathrmB_2

Numerical Answer Type:
Enter a numerical value Answer: 1 to 1 +4 marks

Solution & Explanation

### Core Logic Using Molecular Orbital (MO) Theory, we evaluate the bond order (BO = fracN_b - N_a2) and magnetic nature (unpaired electrons = paramagnetic, all paired = diamagnetic) for each species:
SpeciesMagnetic behaviourBond order
H_2Diamagnetic1
He_2^+Paramagnetic0.5
O_2^+Paramagnetic2.5
N_2^2-Paramagnetic2
O_2^2-Diamagnetic1
F_2Diamagnetic1
Ne_2^+Paramagnetic0.5
B_2Paramagnetic1
### Step 1: Final Selection We need the species that satisfies BOTH conditions: 1. Paramagnetic 2. Bond Order = 1 Looking at the table, B_2 is the only molecule that is paramagnetic (it has 2 unpaired electrons in degenerate pi_2p orbitals) and has a bond order of 1. Total number of such species = 1. ### Pattern Recognition B_2 (10 electrons) and O_2 (16 electrons) are the classic exceptions in MO theory that are paramagnetic despite having an even number of electrons. B_2 has BO = 1, and O_2 has BO = 2. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Chemical Bonding and Molecular Structure

Reference Study Guides

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Q85 jee_main_2024_31_jan_morning Hybridization
The number of species from the following in which the central atom uses sp^3 hybrid orbitals in its bonding is NH_3, SO_2, SiO_2, BeCl_2, CO_2, H_2O, CH_4, BF_3
Numerical Answer. Answer: 4 to 4

Solution

### Core Logic Analyzing the hybridization of the central atom in each species: - NH_3: 3 bp + 1 lp = 4 electron domains rightarrow sp^3 - SO_2: 2 bp + 1 lp = 3 electron domains rightarrow sp^2 - SiO_2: A giant covalent network where each Si is bonded to 4 oxygens tetrahedrally rightarrow sp^3 - BeCl_2: 2 bp + 0 lp = 2 electron domains rightarrow sp - CO_2: 2 bp + 0 lp = 2 electron domains rightarrow sp - H_2O: 2 bp + 2 lp = 4 electron domains rightarrow sp^3 - CH_4: 4 bp + 0 lp = 4 electron domains rightarrow sp^3 - BF_3: 3 bp + 0 lp = 3 electron domains rightarrow sp^2 Total species with sp^3 hybridization: NH_3, SiO_2, H_2O, CH_4. Total count = 4. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Chemical Bonding and Molecular Structure

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