To write the electronic configuration of the first two elements of the d-block, which are Scandium (Sc) and Titanium (Ti), we will follow these steps:
### Step 1: Determine the Atomic Numbers
- Scandium (Sc) has an atomic number of 21.
- Titanium (Ti) has an atomic number of 22.
### Step 2: Write the Electronic Configuration for Scandium (Sc)
1. Start filling the orbitals according to the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to the highest.
2. The order of filling is:
- 1s, 2s, 2p, 3s, 3p, 4s, 3d
3. For Scandium (21 electrons):
- Fill 1s: 1s² (2 electrons)
- Fill 2s: 2s² (2 electrons)
- Fill 2p: 2p⁶ (6 electrons)
- Fill 3s: 3s² (2 electrons)
- Fill 3p: 3p⁶ (6 electrons)
- Now, we have filled 2 + 2 + 6 + 2 + 6 = 18 electrons.
- Next, fill 4s: 4s² (2 electrons)
- Finally, fill 3d: 3d¹ (1 electron)
4. Thus, the electronic configuration for Scandium is:
\[
\text{Sc: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^1
\]
### Step 3: Write the Electronic Configuration for Titanium (Ti)
1. For Titanium (22 electrons):
- Start with the configuration already established for Scandium (18 electrons).
- Continue filling from where Scandium left off.
- Fill 4s: 4s² (2 electrons)
- Now we have 20 electrons.
- Fill 3d: 3d² (2 electrons)
2. Thus, the electronic configuration for Titanium is:
\[
\text{Ti: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^2
\]
### Final Answer
- The electronic configurations are:
- Scandium (Sc): \( 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^1 \)
- Titanium (Ti): \( 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^2 \)
