Final answer:
A liquid made of only one type of atom has no definite shape, taking the shape of its container, and has a definite volume. Mercury is an example of such a liquid at room temperature.
Step-by-step explanation:
When scientists are working with a liquid that is made of only one type of atom, this indicates that they are observing a pure elemental substance in the liquid state. Such a liquid would have a number of characteristic properties. First, since it is a liquid, the substance does not have a definite shape and takes the shape of its container. Additionally, it does have a definite volume because the particles, while moving around each other, are still sufficiently attracted to one another to maintain a consistent volume.
A familiar liquid made of one type of atom would be mercury, which is the only metal that is in liquid form at room temperature. Mercury's high surface tension is an example of properties seen in liquids, which includes the ability of liquids to maintain certain shapes, like droplets, as a result of intermolecular forces.