Which of the following is not an element?

Options

A. sodium
B. gold
C. soil
D. carbon

Explanation

To determine which of the following is not an element, we need to understand the definition of an element and analyze the given options.

### Step-by-Step Solution:

1. **Define an Element**: An element is a pure substance that consists of only one type of atom. It cannot be broken down into simpler substances by chemical means.

2. **Analyze the Options**: We need to examine each option provided in the question to see if it qualifies as an element or not.

- **Option 1: Sodium (Na)**: Sodium is a chemical element with the atomic symbol Na. It consists of only sodium atoms, making it an element.

- **Option 2: Gold (Au)**: Gold is another chemical element, represented by the symbol Au. It is made up of only gold atoms, so it is also an element.

- **Option 3: Soil**: Soil is not a pure substance; it is a mixture that contains various components such as minerals, organic matter, air, and water. Since it is made up of different types of substances, it does not qualify as an element.

- **Option 4: Carbon (C)**: Carbon is a chemical element with the atomic symbol C. It consists solely of carbon atoms, making it an element.

3. **Conclusion**: Based on the analysis, the only option that is not an element is **soil**.

### Final Answer:
Soil is not an element.

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