Assertion A: Energy of 2s orbital of hydrogen atom is greater than that of 2s orbital of lithium.

Reason R: Energies of the orbitals in the same subshell decrease with increase in the atomic number.

Question

Assertion A: Energy of 2s orbital of hydrogen atom is greater than that of 2s orbital of lithium.

Reason R: Energies of the orbitals in the same subshell decrease with increase in the atomic number.

Choose the correct answer:

Canvas Classes · Accepted Answer

Assertion A — True: In H (Z=1), the 2s orbital energy is  eV. In Li (Z=3), due to higher nuclear charge and shielding effects, the 2s energy is lower (more negative, ~ eV). So H's 2s energy is greater (less negative) than Li's 2s energy.

Reason R — True: As atomic number increases, nuclear charge increases, pulling electrons closer and lowering orbital energy. So energies decrease (become more negative) with increasing Z.

R correctly explains A — because Li has higher Z than H, its 2s orbital

More questions from Structure of Atom