What is the atomic mass of calcium?

To find the atomic mass of calcium, we can refer to the periodic table, which lists elements along with their atomic masses. Here’s a step-by-step explanation:

### Steps to Determine Atomic Mass

1. **Identify the Element**: Calcium is represented by the symbol **Ca** on the periodic table.

2. **Locate Calcium on the Periodic Table**: Calcium is found in Group 2 (the alkaline earth metals) and Period 4.

3. **Read the Atomic Mass**: The atomic mass of calcium is typically listed as approximately **40.08 atomic mass units (amu)**. This value is an average that takes into account the natural abundance of its isotopes.

### Why Atomic Mass is Not a Whole Number
- **Isotopes**: Calcium has several isotopes, with \( \text{Ca-40} \) being the most abundant (about 97% of naturally occurring calcium). Other isotopes include \( \text{Ca-42} \), \( \text{Ca-43} \), \( \text{Ca-44} \), and \( \text{Ca-48} \). The atomic mass is a weighted average of these isotopes based on their relative abundance.

- **Natural Abundance**: The atomic mass is not a simple sum of protons and neutrons in the most common isotope but reflects the proportions of all isotopes present in nature.

### Conclusion
Thus, the atomic mass of calcium is approximately **40.08 amu**. This value is important in various fields such as chemistry, biology, and materials science, as it helps in calculations involving moles, stoichiometry, and more.