1.   Each contains five atoms, giving nine normal vibrations.

2.   For example, one molecule of oxygen contains two atoms of oxygen.

3.   One molecule of ammonia contains one atom of nitrogen and three atoms of hydrogen.

4.   First, a gas containing atoms of cesium is introduced into a vacuum microwave cavity that is housed in a silver stovepipe-like structure.

5.   Patients drink a solution of urea that has been manufactured to contain carbon atoms that are heavier than normal.

6.   When this is done on Earth, microbes consume the nutrients and give off gases that contain atoms from the nutrient.