The weight range over which electronic excitations in organic compounds occur, is

Answer

To solve the question regarding the weight range over which electronic excitations in organic compounds occur, we need to clarify that the question is actually about the wavelength range, not weight. Here’s the step-by-step solution:

### Step 1: Understand Electronic Excitations
Electronic excitations refer to the process where electrons in a molecule absorb energy and move from a lower energy level to a higher energy level. This process is crucial in organic compounds as it relates to their interaction with light.

**Hint:** Remember that electronic excitations are linked to the absorption of light, which can be measured using spectrometry.

### Step 2: Identify the Relevant Region of the Electromagnetic Spectrum
The electronic excitations in organic compounds typically occur in the ultraviolet (UV) region of the electromagnetic spectrum. This region is significant because organic compounds often absorb UV light due to their electronic structure.

**Hint:** Recall that different types of electromagnetic radiation interact differently with matter, and UV light is particularly effective for electronic transitions.

### Step 3: Determine the Wavelength Range for UV Light
The UV region of the electromagnetic spectrum generally spans wavelengths from approximately 200 nanometers (nm) to about 400 nm. This range is where most electronic excitations in organic compounds occur.

**Hint:** Look up the electromagnetic spectrum to visualize where the UV region lies in relation to visible light and other types of radiation.

### Step 4: Conclude the Wavelength Range
Based on the information gathered, we conclude that the wavelength range over which electronic excitations in organic compounds occur is from 200 nm to 400 nm.

**Hint:** Make sure to remember that the question is about wavelength, not weight, and the correct terminology is crucial in scientific discussions.

### Final Answer
The wavelength range over which electronic excitations in organic compounds occur is 200 nm to 400 nm (in the UV region).