Which of the following is an element?

Options

A. Silica
B. Glass
C. Water gas
D. Magneslum

Answer

To determine which of the following is an element, we need to analyze each option based on the definition of an element. An element is a pure substance that cannot be broken down into simpler substances by chemical means, and it consists of only one type of atom.

1. **Option A: Silica (SiO2)**
- Silica is a compound made up of silicon (Si) and oxygen (O) atoms. Since it contains more than one type of atom, it is not an element.

2. **Option B: Glass**
- Glass is typically a mixture of silica and other compounds, which means it is not a pure substance made of only one type of atom. Therefore, glass is not an element.

3. **Option C: Water gas**
- Water gas is a mixture of carbon monoxide (CO) and hydrogen (H2). Since it consists of different types of atoms (carbon and hydrogen), it is also not an element.

4. **Option D: Magnesium (Mg)**
- Magnesium is represented by the symbol Mg and consists of only one type of atom. Therefore, magnesium is an element.

**Conclusion:**
The correct answer is **Option D: Magnesium**.