| A | B |
|---|
| atom | the smallest unit of a chemical element that can still retain the properties of that element |
| atomic number | the number of protons in an atom’s nucleus; the atomic number determines an element’s placement on the periodic table |
| compound | a substance made up of a combination of two or more elements held together by chemical bonds that cannot be separated by physical means; has properties unlike those of the elements that make up the compound |
| electron | a stable elementary particle that is negatively charged and orbits the nucleus of an atom |
| element | a substance that cannot be reduced to a simpler substance by chemical means |
| isotope | the form of an element with the same number of protons but a different number of neutrons |
| molecule | the smallest unit of matter of a substance that retains all the physical and chemical properties of that substance; consists of a single atom or a group of atoms bonded together |
| neutral | a particle, object, or system that lacks a net charge |
| neutron | a subatomic particle having zero charge, found in the nucleus of an atom |
| nucleus | the center region of an atom where protons and neutrons are located |
| proton | a subatomic particle having a positive charge and which is found in the nucleus of an atom |
