1. Proton a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.
2. Neutron a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
3. Electron a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.
4. Isotope each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
5. Element each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e., the number of protons in the nuclei of its atoms.
6. Ionic A chemical bond formed between two ions with opposite charges. Ionic bonds form when one atom gives up one or more electrons to another atom. These bonds can form between a pair of atoms or between molecules and are the type of bond found in salts.
7. Covalent relating to or denoting chemical bonds formed by the sharing of electrons between atoms.
8. Mixture a substance made by mixing other substances together.
9. Pure Substance Pure Substances: Concept and Properties. ... The pure substance within chemistry is a very simple concept to grasp. Pure substances are defined as substances that are made of only one type of atom or only one type of molecule (a group of atoms bonded together). The measure of whether a substance is pure is known as purity.
10. Chemical Change Chemistry. a usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance: The formation of rust on iron is a chemical change. Compare physical change.
11. Atom the basic unit of a chemical element.
12. Ion an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
13. Monatomic and Polyatomic A monatomic ion is an ion consisting of a single atom. If an ion contains more than one atom, even if these atoms are of the same element, it is called a polyatomicion. For example, calcium carbonate consists of the monatomic ion Ca2+ and thepolyatomic ion CO32−.
14. Cation and Anion Cations and anions are both ions. The difference between a cation and an anion is the net electrical charge of the ion. Ions are atoms or molecules which have gained or lost one or more valence electrons giving the ion a net positive or negative
15. Molecule (diatomic and polyatomic) a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
16. Compound A compound is a substance formed when two or more chemical elements are chemically bonded together. ... The type of bonds holding elements together in acompound can vary: two common types are covalent bonds and ionic bonds. Theelements in any compound are always present in fixed ratios.
17. Physical Change Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.
