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Ch. 7-8 Definitions
Ch. 7-8 Notes
Term | Definition |
---|---|
Atom | is the smallest piece of an element that still represents that element |
Electron | is a particle with one negative charge |
Nucleus | most of an atom's mass and positive charge is concentrated in a small area in the center of the atom |
Proton | is an atomic particle that has one positive charge |
Neutron | is a neutral particle that exists in the nucleus of an atom. |
Electron Cloud | is an area around an atomic nucleus where an electron is most likely to be located |
Atomic Number | number of protons in an atom of an element |
Isotopes | are atoms of the same element that have different numbers of neutrons. Most elements have several isotopes |
Mass Number | is the sum of the number of protons and neutrons in an atom |
Average Atomic Mass | is the average mass of the element's isotopes, weighted according to the abundance of each isotope |
Ion | is an atom that is no longer neutral because it has gained or lost electrons |
Metals | often shiny, good conductors of electricity and thermal energy: easily pulled into wires and hammered into sheets |
Metalloids | have properties in common with both metals and nonmetals often used as semiconductors in electronic devices |
Nonmetals | poor conductors of thermal energy and electricity, most are gases at room temperature: solid forms tends to be brittle |
Chemical Bonds | is a force that holds two or more atoms together |
Valence Electrons | is an outermost electron of an atom that participates in chemical bonding. These outermost electrons are the only electrons involved in chemical bonding |
Electron Dot Diagram | a model that represents valence electrons in an atom as dots around the element's chemical symbol |
Covalent Bond | is a chemical bond formed when two atoms share one or more pairs of valence electrons. The atoms then form a stable covalent compound. |
Molecule | is a group of atoms held together by covalent bonding that acts as an independent unit |
Chemical Formula | is a group of chemical symbols and numbers that represent the elements and the number of atoms of each element that make up a compound |
Ionic Bond | the attraction between positively and negatively charged ions in an ionic compound |
Metallic Bond | is a bond formed when many metal atom share their pooled valence electrons |