The correct order of increasing first ionization energy is

Options

A. `Ca lt K lt Ne lt P lt F`
B. `F lt Ca lt N e lt P lt K`
C. `K lt Ca lt Plt F lt Ne`
D. `Ne lt F lt P lt Ca lt K`

Answer

To determine the correct order of increasing first ionization energy, we need to consider the trends in the periodic table. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understand Ionization Energy
- Ionization energy is defined as the energy required to remove an electron from an isolated gaseous atom.

### Step 2: Trends Across a Period
- As we move from left to right across a period in the periodic table, the ionization energy generally increases. This is due to the increase in nuclear charge (more protons) which pulls the electrons closer to the nucleus, making them harder to remove.

### Step 3: Trends Down a Group
- Conversely, as we move down a group in the periodic table, the ionization energy decreases. This is because the atomic size increases (more electron shells), which means the outermost electrons are further from the nucleus and are held less tightly, making them easier to remove.

### Step 4: Identify the Elements
- Let’s consider the elements mentioned: Neon (Ne), Fluorine (F), Phosphorus (P), Calcium (Ca), and Potassium (K).
- Neon (Noble gas) has the highest ionization energy due to its stable electron configuration.
- Fluorine has a high ionization energy but is lower than Neon.
- Phosphorus is in the same period as Calcium and Potassium but has a higher ionization energy than both.
- Calcium and Potassium are in the same group, with Calcium having a higher ionization energy than Potassium.

### Step 5: Arrange the Elements
- Based on the trends and the elements:
- Highest: Neon (Ne)
- Next: Fluorine (F)
- Then: Phosphorus (P)
- Followed by: Calcium (Ca)
- Lowest: Potassium (K)

### Final Order of Increasing First Ionization Energy
- The correct order of increasing first ionization energy is:
- Potassium (K) < Calcium (Ca) < Phosphorus (P) < Fluorine (F) < Neon (Ne)

### Summary
- The final order is: K < Ca < P < F < Ne