Vocab. Words Tools A B Ionic Bond type of bond that gains electrons from another atom and loses electrons from its outer shell Electrons directly involved in chemical reactions between atoms; one of three atomic particles Isotopes hydrogen, deuterium, and tritium are examples of ______ Gas state of matter has no definite shape and no definite volume Liquid state of matter that has no definite shape but has a definite volume Solid state of matter has a definite shape and definite volume Number of Naturally Occuring Elements 92 Number of Named Elements 106 pH5 is ___ more acidic than pH6. 10 Times Inductive Reasoning reasoning based on observing and testing Deductive Reasoning reasoning based on facts or already established principles SurfaceTension measure of how difficult it is to stretch or break the surface of a liquid Valence bonding capacity of an atom equals the number of unpaired electrons in the outer shell Molecular Formula formula that indicates only the kinds an dnumbers of atoms in a molecule Structural Formula indicates both number and type of atoms and also the bonding within a molecule Potential Energy energy stored in matter as a consequence of the relative position of masses Energy ability to do work Dalton measurement unit for atomic mass Reactant starting material in chemical reaction Chemical Reaction process leading to chemical changes in matter; involves making and breaking of bonds Acid Precipitation rain, snow, etc. with pH below 5.6; damages or destroys organisms by acidifying lakes, streams, etc. Buffers chemical substance that reists changes in pH by accepting ions fromdonating H+ ions to solutions Potential Hydrogen pH- describes acidity of solution Base compound accepts H+ ions and removes them from solution Acid chemical compound that donates H+ ions to solutions Solute substance dissolved in a solution Solvent dissolving agent in a solution Solution fluid misture of two or more substances, consisting of a dissolving agent and solute Temperature measure of intensity of heat, reflecting average kinetic energy or speed of molecules Heat amount of energy associated with movement of atoms and molecules Adhesion tendency of different kinds of molecules to stick together Cohesion tendency of molecules of same kind to stick together Hydrogen Bond weak chemical bond formed when partially positive hydrogen atom is attracted to negative atom Polar Molecule molecule containing polar covalent bonds; has a slightly negative pole and two slightly postive ones Polar Covalent Bond chemical bond in which shared electrons pulled close to more electronegative atom, making it partially negative and the other partially positive Oxygen element considered most electronegative of all elements Nonpolar Covalent Bond attraction between atoms that share one or more paris of electrons equally because atoms have similar electronegativity Electronegativity tendency for an atom to pull electrons toward itself Double Bond type of covalent bond in which two atoms share two pairs of electrons Molecule two or more atoms held together by covalent bonds Covalent Bond strong chemical bond in which two atoms share one or more pairs of outer shell electrons Chemical Bond attraction between two atoms resulting from a sharing of outer shell electrons or presence of opposite charges on the atoms; bonded atoms gain complete outer electron shells Ion atom or molecule with electrical charge resulting from gain or loss of one or more electrons Electron Shell Energy level at which an electron orbits the nucleus of an atom Radioactive Isotope isotope whose nucleus decays spontaneously giving off particles and energy Isotope variant form of atom; have same number of protons but different number of neutrons Mass Number sum of numbers of protons and neutrons Atomic Weight approximate total mass of an atom Atomic Number number of protons in each atom of a particular element Nucleus atom's central core contains protons and neutrons Neutron subatomic particle that has a neutral charge and lives in the nucleus Electron subatomic particle with negative charge and lives outside the nucleus Proton subatomic particle found in the nucleus and has a positive charge Atom smallest unit of matter and named from Greek word meaning indivisible Compound substance containing two or more elements in a fixed ratio CHON- Carbon, Hydrogen, Oxygen, Nitrogen four elements essential to life; these four make up 96% of human body Trace Elements materials essential to some organisms but only in minute quantites Chemical Element substance that can't be broken down to other substances by ordinary chemical means Matter anything that occupies space and has mass