Chemistry Terms Study Exam Question And Correct Answers.

Matter - correct answer Anything that has mass and takes up space Atom - correct answer The smallest unit of matter; composed of protons, neutrons and electrons Nucleus - correct answer The center of an atom; composed of protons and neutrons Proton - correct answer Positively charged subatomic particle Electron - correct answer Negatively charged subatomic particle Neutron - correct answer Subatomic particle with no charge Element - correct answer A pure substance made from only one type of atom Atomic number - correct answer The number of protons in an atom; identifies the atom/element Mass number - correct answer The mass of an atom; calculated by adding the number of protons plus the number of neutrons Compound - correct answer A substance made by chemically combining two or more atoms Ionic bond - correct answer A bond created when electrons are donated between atoms, creating opposite charges Covalent bond - correct answer A bond created when electrons are shared between the valences of two atoms Polar covalent bond - correct answer A bond where electrons are shared unevenly between the valences of two atoms; creates poles with opposite charges Octet rule - correct answer The principle that states that the most stable configuration for a valence is to have eight electrons Valence - correct answer The outermost energy level of an atom Ion - correct answer A charged atom or compound; created by adding or losing electrons Isotope - correct answer Forms of an atom with different numbers of neutrons Cation - correct answer A positively charged ion Anion - correct answer A negatively charged ion Hydrogen bond - correct answer A bond created when a hydrogen in a polar bond attracts to a nearby electronegative atom van der Waals forces - correct answer Attractions between molecules due to temporary dipoles Solute - correct answer The substance that is dissolved in a solution Solvent - correct answer The substance that dissolves the solute in a solution Specific heat - correct answer A measure of how well a substance absorbs heat energy Acid - correct answer A substance that releases hydrogen ions in a solution; lowers pH of the solution Base - correct answer A substance that accepts hydrogen ions (or releases hydroxide ions in a solution; raises pH of the solution Buffers - correct answer A substance that converts strong acids or bases to weak ones Reactants - correct answer The starting materials in a chemical reaction Catabolic - correct answer A reaction that breaks molecules down (breaks chemical bonds) Anabolic - correct answer A reaction the builds molecules (forms chemical bonds) Endergonic - correct answer A reaction that absorbs energy Exergonic - correct answer A reaction that releases energy Electronegativity - correct answer The tendency of an atom to draw electrons to itself