Chlorine is one of the most common elements found on Earth's crust. The name comes from the Greek word for light green, which is how the gas appears in elemental form. It has 17 protons and two stable isotopes giving it a standard atomic weight of 35.45, which makes chlorine the second lightest halogen. It also has the highest electron affinity of any element making it a very strong oxidizer. This means that chlorine will readily steal electrons from other elements. In fact the vast majority of chlorine found on Earth is in the form of the chloride anion (a chlorine atom which has already stolen an extra electron), which will form ionic compounds with many cations (like metals). It is in this form that humans are most familiar with chlorine, as in ionic compound sodium chloride, which we know of as table salt. Chloride ions are important to many chemical and industrial processes including the making of usable chlorine and sodium hydroxide, and desalination and testing of potable water.
We continue our coverage of the Boston Time Capsule with updates from our recent visit to the Museum of Fine Arts, exhibit showing what was discovered inside the second Capsule recovered. The interest in this Time Capsule has been highly documented by many world news organizations because two well-known American patriots, Paul Revere and Sam Adams, were involved. Photos we were allowed to take are shown below.