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| atom | the basic building block of matter and consists of subatomic particles (proton, neutron and electron) |
| arrow | symbol used to represent change in a chemcial equation |
| balanced chemical equation | chemical equation with the same number of atoms of each element on both sides of the equation |
| chemical bond | force that holds together the atoms in a compound |
| chemical equation | chemcial formulas and symbols that represent a chemical reaction |
| chemical formula | tells which elements are in a compound and their ratios |
| chemical property | characteristic of a substance that indicates whether it can undergo a chemical change |
| chemical reaction | the breaking of bonds to form new substances (products), atoms are rearranged in a chemical reaction |
| chemical reactivity | ability to chemically combine |
| chemically stable | outer energy level is filled with electrons |
| compound | a substance made of two or more elemnets that are chemically combined |
| covalent bond | chemical bond formed from shared electrons |
| electron | subatomic particle in an atom with a negative charge; occuppies the energy levels in an atom |
| element | substance in which all the atoms in a sample are alike |
| endothermic reaction | chemical reaction which takes in heat energy, more energy is required to break the bonds in reactants than released in products |
| energy | the ability to do work or cause change |
| energy level | a region around the nucleus of an atom where electrons are most likely to be found; only a certain number of electrons can be found in each energy level of an atom |
| exothermic reaction | chemical reaction where heat energy is given off; less energy is required to break the bonds in reactants than is released in products. |
| inorganic compounds | compounds that do not contain carbon |
| ion | a positively or negatively charged atom |
| ionic bond | a chemical bond between oppositely charged ions |
| Law of Conservation of Energy | energy cannot be created or destroyed only changed from one form to another |
| Law of Conservation of Matter (Mass) | regardless of how substances within a closed system are changed, the total mass remains the same. |
| mass | measure of how much matter is in an object |
| metal | typically a hard, shiny solid, malleable and shinny, solids at room temperature, good conductors of heat and electricity, located to the left of the stairstep line on the periodic table |
| mixture | matter that consists of two or mosre substances not chemically combined |
| nonmetals | most are gases or brittle solids at room temperature, not malleable or ductile, a poor conductor of heat and electricity, typically not shiny, located to the right of the stairstep line on the periodic table |
| organic compounds | most compounds that contain carbon |
| physical change | a change in size, shape or state of matter |
| product | substance that is produced in a chemical reaction from reactants; on the right of the arrow or yield sign |
| reactant | a substance that enters into and is altered in the course of a chemical reaction; on the left of the arrow or yield sign |
| substance | either an element or compound which cannot be reduced to basic componenets by physical processes |
| oxidation number | shows and element's combining ability |
| coefficient | number placed in front of a chemical formula or symbol to represent the number of units of the substance |
| acid | substance that produces hyrogen ions (H+) in solution or any solution that has a pH less than 7 |
| acidity | the property of being an acid |
| base | substance that produces hydroxide ions (OH-) in solution or any soluction that has a pH greater than 7 |
| basicity | the property of being a base |
| chemical change | change from one substance to another substance |
| chemical property | characteristic of a substance that indicates whether it can undergo a chemical change includes acidity, basicity, combustion and reactivity |
| combustibility | ability of a substance to catch fire and burn easily |
| compound | a substance made of two or more elements that are chemically combined |
| hydrogen ions | a positively charged ion (H+) formed of a hydrogen atom that has lost its electron |
| hydroxide ions | a negatively charged ion (OH-) made of ozygen and hydrogen |
| neutral | a pH of 7; not an acid or a base |
| pH | a measure of hydroniuym (H+) ions in a solution |
| physical property | any such characteristic of a material that you can observe without changing the substances that make up the matter: shape, denisty, solubility, odor, melting point, boiling point and color |
| reactivity | ability to combine with another substance |
| salt | formed by the negative ions from an acid combing with the positive ions from a base |
| solubility | the amount of a substance (solute) that will dissolve in a solvent; generally expressed as the maximum number of grams of solute that will dissolve in 100g of a solvent at a specific temperature |
| solution | mixture that appears to have the same composition, color, density and taste throughout |
| substance | either an element or compound which cannot be reduced to basic components by physical processes |
| nuclear energy | the energy stored in the nucleus of an atom |
| nuclear fission | splitting a nucleus into tow smaller masses |
| nuclear fusion | two nuclei combining into a larger nucleus |
| nuclear reaction | a reaction that involves splitting of a nucleus of an atom or the fusing of two nuclei; produce much more energy than chemical reactions |
| nuclear waste | radioactive by-products that result when radioactive material are used |
| nucleus | positively charged center of an atom; contains protons and neutrons |
| matter | anything that has mass and takes up space |
| radioactivity | emmission of high-energy particles or radiation from an unstable nucleus |
