Explanation

Formula: Bond order = (Nb - Na) / 2

For O2:

Total electrons = 16

Configuration: σ1s² σ_1s² σ2s² σ_2s² σ2pz² π2px² π2py² π_2px¹ π_2py¹

Bonding electrons (Nb) = 10

Antibonding electrons (Na) = 6

Bond order = (10 - 6) / 2 = 4/2 = 2

Means O=O double bond, which also explains its 2 unpaired electrons (paramagnetic).

Last verified on 29-10-2026

Explanation

• Degenerate orbitals are orbitals that have the same energy.
• The three p orbitals (px, py, pz) in an isolated atom have the same energy.
• They have different directions but equal energy.

Last verified on 29-10-2026

Explanation

1. 1st line (H-alpha) = electron from n=3 to n=2 : n1=2, n2=3
2. 2nd line (H-beta) = electron from n=4 to n=2 : n1=2, n2=4
3. 3rd line (H-gamma) = electron from n=5 to n=2 : n1=2, n2=5

Explanation

• KCl has formula mass.
• KCl is an ionic compound.
• It exists as a crystal lattice, not discrete molecules.
• So we use formula mass.

Additional information:

• NH₃, C₆H₁₂O₆, CO₂ are covalent molecules. 
• They exist as discrete molecules.
• So we use molecular mass.

Last verified on 29-10-2026

Explanation

Molar mass of water (H₂O) = 2(1) + 16 = 18 g/mol

Moles = Mass / Molar mass

Moles = 90 / 18 = 5 moles

Last verified on 29-10-2026