To determine the correct order of ionization energy for the given elements, we will analyze each set of elements based on their electronic configurations and periodic trends. Here’s a step-by-step breakdown:
### Step 1: Understanding Ionization Energy
- **Definition**: Ionization energy is the energy required to remove the outermost electron from an atom in its gaseous state.
- **Trend**: Ionization energy generally increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table.
### Step 2: Analyzing the First Set (Cu, Ag, Au)
- **Elements**: Copper (Cu), Silver (Ag), Gold (Au)
- **Trend**: As we move down the group, the atomic size increases due to additional electron shells, making it easier to remove the outermost electron.
- **Conclusion**: The order of ionization energy is Au > Cu > Ag. Thus, this order is incorrect as given (Ag, Cu, Au).
### Step 3: Analyzing the Second Set (Sc, Y, La)
- **Elements**: Scandium (Sc), Yttrium (Y), Lanthanum (La)
- **Trend**: Similar to the previous set, as we move down the group, the atomic size increases.
- **Conclusion**: The order of ionization energy is Sc > Y > La, which is correct.
### Step 4: Analyzing the Third Set (Ni, Pd, Pt)
- **Elements**: Nickel (Ni), Palladium (Pd), Platinum (Pt)
- **Trend**: Platinum has a filled 4f subshell, leading to less shielding and a smaller size, thus requiring more energy to remove an electron.
- **Conclusion**: The order of ionization energy is Pt > Pd > Ni, which is incorrect as given (Pd, Pt, Ni).
### Step 5: Analyzing the Fourth Set (B, Al, Ga)
- **Elements**: Boron (B), Aluminium (Al), Gallium (Ga)
- **Trend**: Gallium has a filled d subshell which causes less shielding, resulting in a smaller size compared to Aluminium.
- **Conclusion**: The order of ionization energy is B > Ga > Al, which is correct.
### Final Conclusion
Based on the analysis, the correct orders of ionization energy are:
1. Sc > Y > La (correct)
2. B > Ga > Al (correct)
### Summary of Correct Orders
- **Correct Orders**:
- Scandium, Yttrium, Lanthanum
- Boron, Gallium, Aluminium
