The `EN` of the elements `C, N, Si` and `P` increases in the order of `"______"` .

Explanation

To determine the order of electronegativity (EN) for the elements carbon (C), nitrogen (N), silicon (Si), and phosphorus (P), we need to analyze their positions in the periodic table and apply the general trend of electronegativity.

### Step-by-Step Solution:

1. **Identify the Position of Elements in the Periodic Table**:
- Carbon (C) is in Group 14 (or IV) and Period 2.
- Nitrogen (N) is in Group 15 (or V) and Period 2.
- Silicon (Si) is in Group 14 (or IV) and Period 3.
- Phosphorus (P) is in Group 15 (or V) and Period 3.

2. **Understand Electronegativity Trends**:
- Electronegativity increases across a period (from left to right).
- Electronegativity decreases down a group (from top to bottom).

3. **Compare Electronegativity of the Elements**:
- Between C and N: Since N is to the right of C in the same period, N has a higher electronegativity than C.
- Between C and Si: C is above Si in the same group, so C has a higher electronegativity than Si.
- Between N and P: N is above P in the same group, so N has a higher electronegativity than P.
- Between Si and P: Si is above P in the same group, so Si has a higher electronegativity than P.

4. **Establish the Order**:
- From the comparisons, we can summarize:
- N > C > Si > P
- Therefore, the order of increasing electronegativity is: Si < P < C < N.

5. **Final Answer**:
- The electronegativity of the elements C, N, Si, and P increases in the order of: **Si < P < C < N**.