Answer:
An atom is a particle of matter that uniquely defines achemical element. An atom consists of a central nucleus that is usually surrounded by one or more electrons. ... The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons. A proton is positively charged.
Slow down because liquids have less movement than gases
Mixtures are combinations of materials that can be separated by in most cases time. For instance, oil and water is a mixture. You can tell this by placing the two chemicals in a container and shaking them. They will mix and look like one substance, however, they will separate into the two liquids after some time is given. Assuming that "pure substance" is a solution, a substance is similar to a mixture, but the materials used in the solution are not separable. Over time the materials in the containing will not separate. I believe this is the answer you are looking for.
