Which represents alkali metals (i.e. `1^(st)` group metals) based on `(IE)_(1)` and `(IE)_(2)` value (in `KJ//mol)`?

Options

A. `{:(,(IE)_(1),(IE)_(2)),(X,500,1000):}`
B. `{:(,(IE)_(1),(IE)_(2)),(Y,600,2000):}`
C. `{:(,(IE)_(1),(IE)_(2)),(Z,550,7500):}`
D. `{:(,(IE)_(1),(IE)_(2)),(M,700,1400):}`

Answer

To determine which values represent alkali metals based on their first ionization energy (IE₁) and second ionization energy (IE₂), we can follow these steps:

### Step 1: Understand the Concept of Ionization Energy
- Ionization energy is the energy required to remove an electron from an atom. The first ionization energy (IE₁) is for removing the first electron, and the second ionization energy (IE₂) is for removing the second electron.

### Step 2: Analyze Alkali Metals
- Alkali metals (Group 1) have the general electronic configuration of ns¹. For example, sodium (Na) has the configuration 1s² 2s² 2p⁶ 3s¹. When the first electron is removed, it achieves a stable noble gas configuration (Neon in this case).

### Step 3: Compare Ionization Energies
- The first ionization energy (IE₁) for alkali metals is relatively low because they can easily lose their single valence electron. However, the second ionization energy (IE₂) is significantly higher because it involves removing an electron from a stable noble gas configuration.

### Step 4: Evaluate Given Options
- We need to look for a pair of values where IE₂ is much greater than IE₁. This indicates that after losing the first electron, the atom achieves a stable configuration, making it difficult to remove the second electron.

1. **Option 1**: IE₁ = 500 kJ/mol, IE₂ = 1000 kJ/mol (Not a large difference)
2. **Option 2**: IE₁ = 600 kJ/mol, IE₂ = 2000 kJ/mol (Not a large difference)
3. **Option 3**: IE₁ = 550 kJ/mol, IE₂ = 7500 kJ/mol (Very large difference)
4. **Option 4**: IE₁ = 700 kJ/mol, IE₂ = 1400 kJ/mol (Not a large difference)

### Step 5: Identify the Correct Option
- The only option where the second ionization energy is significantly greater than the first ionization energy is **Option 3** (IE₁ = 550 kJ/mol, IE₂ = 7500 kJ/mol). This large difference indicates that after losing the first electron, the alkali metal achieves a stable noble gas configuration, making it very difficult to remove the second electron.

### Conclusion
- The correct representation of alkali metals based on their ionization energy values is **Option 3** (IE₁ = 550 kJ/mol, IE₂ = 7500 kJ/mol).

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