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Biology 2
2.1 and 2.2
Term | Definition |
---|---|
atom | the study of chemistry begins with the basic unit of matter |
nucleus | strong forces bind protons and neutrons together to form the nucleus |
electron | a negatively charged particle with only 1/1840 the mass of a proton |
element | a pure substance that consists entirely of one type of atom |
isotope | atoms of the same element that differ in the number of neutrons they contain |
compound | a substance formed by the chemical combination of two or more elements in definite proportions |
ionic bond | is formed when one or more electrons are transferred from one atom to another |
ion | positively and negatively charges atoms |
molecule | the smallest unit of most compounds |
covalent bond | the moving electrons actually travel about the nuclei of both atoms |
van der Waals forces | Chemists call such intermolecular forces of attraction van der Waals forces |
hydrogen bond | the attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge |
cohesion | an attraction between molecules of the same substance |
adhesion | an attraction between molecules of different substances |
mixture | a material composed of two or more elements or compounds that are physically mixed together but not chemically combined |
solution | all the components of a solution are evenly distributed throughout the solution |
solute | the substance that is dissolved |
solvent | the substance in which the solute dissolves |
suspension | mixtures of water and non-dissolved material |
pH scale | a measurement system to indicate the concentration of H+ ions in solution |
acid | any compound that forms H+ ions in solution |
base | a compound that produces hydroxide ions in solution |
buffer | weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH |