ecs-biology on September 10, 2008
Important terms used in the understanding of basic chemistry.
Log in to favorite or report as inappropriate.Terms | Definitions |
|---|---|
matter | anything that occupies space and has mass |
element | a pure substance that cannot be broken down into other substances by chemical reactions |
trace element | an element found in very small amounts, yet essential for good health |
compound | substance containing two or more elements chemically combined in a fixed ratio |
atom | the smallest particle of an element that retains the properties of the element |
proton | subatomic particle having a positive charge; found in nucleus |
electron | subatomic particle having a negative charge; not in nucleus but surrounds it |
neutron | subatomic particle without a charge; found in nucleus |
nucleus | protons and neutrons together; make up the center of an atom |
atomic number | identifies a specific element; equals the number of protons in an atom of each element |
radioactive isotope | an unstable atom in which the nucleus decays (breaks down) releasing particles and energy (radiation) |
isotope | atoms having the same numbers of protons but different numbers of neutrons |
ionic bond | occurs when atoms transfer electrons to other atoms |
ion | atom that has lost or gained electrons |
covalent bond | occurs when atoms share electrons |
molecule | atoms that are held together by covalent bonds (they share electrons) |
chemical reaction | interaction of substances that lead to the formation of new substances |
reactant | the starting materials for a reaction; found on left side of chemical equation |
product | ending materials of a reaction; found on right side of chemical equation |
organic compound | substance made of two or more elements, one being carbon |
inorganic compound | substance made of two or more elements, none of which is carbon |
reactive | refers to an atom having energy levels that are not filled, thus it forms bonds |
inert | refers to an atom having filled energy levels, thus it does not form bonds |
valence electrons | electrons in the outermost energy level; they are involved in bond formation |
single bond | a covalent bond in which one pair of electrons is shared |
double bond | a covalent bond in which four valence electrons are shared between two atoms |
chemical formula | indicates the number and types of atoms in a molecule |
structural formula | shows the number and types of atoms in a molecule and how they are arranged |
space-filled model | is a 3-D representation of a molecule |
chemical reaction | indicates the formation of new substances from previous substances |
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