atom


atom
The smallest particle of an elementA substance containing only one kind of atom and that therefore cannot be broken down into component substances by chemical means. that can be involved in chemical combination with another element; an atomThe smallest particle of an element that can be involved in chemical combination with another element; an atom consists of protons and neutrons in a tiny, very dense nucleus, surrounded by electrons, which occupy most of its volume. consists of protons and neutrons in a tiny, very dense nucleusThe collection of protons and neutrons at the center of an atom that contains nearly all of the atoms's mass., surrounded by electrons, which occupy most of its volume.