Frequently Asked Question

The term symbols for an atom with configuration s¹p¹ are:
1. ³P₂: This term symbol represents the highest spin multiplicity (S=1, 2S+1=3) and the highest total orbital angular momentum (L=1, 2L+1=3). It's also the ground state.
2. ³P₁: This term symbol also has a spin multiplicity of 3 but a lower L value (L=1).
3. ³P₀: This term symbol has a spin multiplicity of 3 and the lowest L value (L=0).
4. ¹P₁: This term symbol has the lowest spin multiplicity (S=0, 2S+1=1) and an L value of 1.
Working:
1. Spin Multiplicity (2S+1):
- The s¹ configuration has one unpaired electron (spin = +1/2), and the p¹ configuration has another unpaired electron (spin = +1/2).
- The total spin angular momentum (S) is the sum of individual spins: S = +1/2 + 1/2 = 1.
- Spin multiplicity = 2S + 1 = 2(1) + 1 = 3.
2. Total Orbital Angular Momentum (L):
- The s orbital has l = 0.
- The p orbital has l = 1.
- Total L can be found by adding the individual l values: L = 0 + 1 = 1.
- However, since we have two electrons, we can also have L = 1 - 1 = 0.
3. Term Symbol:
- The term symbol is written as: ²S+¹L_J
- We know the spin multiplicity (2S+1) is 3.
- We have two possible L values: 1 (³P) and 0 (³S).
- The total angular momentum J can be determined using the Hund's rules and the formula: J = |L + S| to |L - S|.
Therefore, the possible term symbols are ³P₂ (L=1, J=2), ³P₁ (L=1, J=1), ³P₀ (L=1, J=0), and ¹P₁ (L=1, J=1).
Yes, it is possible for L to be 0. This occurs when the orbital angular momenta of the two electrons are aligned oppositely, canceling each other out. This results in the ³S term symbol.