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Science Vocab
Science words
Term | Definition |
---|---|
Atom | the basic unit of a chemical element. |
Element | is a pure substance which cannot be broken down by chemical means, consisting of atoms which have identical numbers of protons in their atomic nuclei. |
Molecule | a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction. |
Compound | a substance formed from two or more elements chemically united in fixed proportions. |
Atomic number | the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. |
Mass number | the total number of protons and neutrons in a nucleus. |
Atomic weight | another term for atomic mass. |
Valence electron | is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed |
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. |
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. |
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. |
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 |
Radioisotope | a radioactive isotope. |
Electron configuration | electronic structure, the arrangement of electrons in energy levels around an atomic nucleus. |
Bond | a strong force of attraction holding atoms together in a molecule or crystal, resulting from the sharing or transfer of electrons. |
Polar bond | is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. |
Nonpolar bond | A bond between 2 nonmetal atoms that have the same electronegativity and therefore have equal sharing of the bonding electron pair. |
Hydrogen bond | a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other. |
Solvent | able to dissolve other substances. |
Solution | a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent). |
Solute | the minor component in a solution, dissolved in the solvent. |
Hydrophobic | tending to repel or fail to mix with water. |
Hydrophilic | having a tendency to mix with, dissolve in, or be wetted by water. |
Amino acid | a simple organic compound containing both a carboxyl (—COOH) and an amino (—NH2) group. |
Nucleotide | a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA. |
Peptide bond | a covalent bond formed by joining the carboxyl group of one amino acid to the amino group of another, with the removal of a molecule of water. |
Lipid | any of a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. They include many natural oils, waxes, and steroids. |
Saturated fat | a type of fat containing a high proportion of fatty acid molecules without double bonds, considered to be less healthy in the diet than unsaturated fat. |
Saccharide | another term for sugar |
Specific heat | the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree). |