In the lithium iodide crystal, the Li I distance is 3.02 .

1. Matter can change either physically or chemically. 1. In our body systems, we often use special chemicals called enzymes to help chemically change matter. Elements A. Elements are the building blocks of chemical matter. These are substances that cannot be broken down into simpler substances by ordinary chemical reactions. B. There are more than 100 elements. Most elements are naturally occurring, but there are some man-made elements. Elements are given names and abbreviations (chemical symbols) indicated by letters.