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| Theory | A logical, time-tested explanation for events that occur in the natural world |
| Law | Summarizing statement of observed experimental facts that has been tested many times and is generally accepted as true |
| Scientific Method | 1. Stating the Problem 2. Gathering the Information 3. Forming a hypothesis 4. Experimenting 5. Recording and Analyzing the data 6. Stating a conclusion 7. Repeating the work |
| Hypothesis | A proposed solution to a scientific problem |
| Variable | The one factor that is being tested in an experiment |
| Control | experiment run without a variable, to show that any data from experimental setup was due only to the variable that was being tested |
| Data | Recorded observations and measurements |
| Metric System | Standard system of measurement |
| Meter | Basic unit of length |
| Centimeter | one hundredth of a meter |
| Millimeter | one thousandth of a meter |
| Kilometer | one thousand meters |
| Liter | basic unit of volume |
| Milliliter | one thousandth of a liter |
| Cubic Centimeter | Metric unit used to measure volume of solids |
| Kilogram | basic unit of mass |
| Gram | one thousandth of a kilogram |
| Milligram | one thousandth of a gram |
| Density | measurement of how much mass is contained in a given voluem of an object; mass per unit volume |
| Celcius | water freezes at 0 water boils at 100 |
| Dimensional Analysis | method of converting one unit to another |
| Conversion Factor | Fraction that always equals one, which is used for dimensional analysis |
| Meniscus | point at the bottom of the curve of a liquid in a graduated cylinder |
| Matter | Anything that has mass and volume |
| Property | characteristic of a substance |
| Mass | amount of matter in an object |
| Inertia | tendency of objects to remain in motion or to stay at rest unless acted upon by an outside force |
| Weight | measure of the force of attraction between two objects due to gravity |
| Gravity | force of attraction that depends on the mass of two objects and the distance between them |
| Volume | amount of space an object takes up |
| Physical Property | characteristic that tells one type of matter from another and can be observed without changing its identity |
| Phase | state in which matter can exist |
| Solid | Phase in which matter has a definite shape and volume |
| Crystal | solid in which the particles are arranged in a regular repeating pattern |
| Liquid | Phase in which matter has a definite volume and an indefinite shape |
| Gas | phase in which matter has no definite shape or volume |
| Plasma | phase in which matter is extremely high in energy and cnnot be contained by ordinary matter |
| Melting | When a solid turns into a liquid |
| Melting Point | Point at which a solid turns into a liquid |
| Freezing | When a liquid turns into a solid |
| Freezing Point | Point at which a liquid turns into a solid |
| Vaporization | change of a liquid to a gas |
| Evaporization | vaporization that takes place at the surface of a liquid |
| Boiling | when a liquid changes to a gas |
| Boiling Point | the point at which a liquid changes to a gas |
| Condensation | when a gas changes to a liquid |
| Sublimation | when a solid changes to a gas, without going through the liquid phase |
| Chemical Property | property that describes how a substance changes into a new substance |
| Flammability | ability to burn |
| Chemical Change | process by which a substance becomes a new and different substance |
| Chemical Reaction | process in which substaces undergo phisical and chemical changes that result in the formation of new substances |
| Mixture | matter that consists of two or more substances mixed but not chemically combined |
| Heterogeneous Mixture | substance that does not appear to be the same throughout |
| Homogeneous Mixture | mixture that appears to be the same throughout |
| Colloid | homogeneous mixture in which the particles are mixed together but not dissolved |
| Solution | homogeneous mixture of twho or more substances in a single physical state |
| Solute | substance that is dissolved in a solution |
| Solvent | substance that does the dissolving in a solution |
| Soluble | can be dissolved in another material |
| Insoluble | unable to be dissolved in another material |
| Solubility | measure of how much of a soute can be dissolved in a given amount of solvent under certain conditions |
| Alloy | solution of 2 metals or a metal and a nonmetal that has the properties of a metal |
| Pure Substance | substance made of one kind of material having definite properites |
| Element | simplest type of pure substance |
| Atom | smallest part of an element that has all the properties of an element |
| Chemical Symbol | shorthand way of representing an element |
| Compound | substance made up of molecules that contain more than one kind of atom |
| Molecule | combination of atoms formed by a covalent bond |
| Chemical Formula | combination of chemical symbols usually used to represent a compound |
| Subscript | number placed to the lower right of a chemical symbol to indicate the number of atoms of the element in the compound |
| Chemical Equation | expression in which symbols formulas and numbers are used to represent a chemical reaction |
| Coefficient | number that is placed in front of a symbol or a formula indicating how many atoms or molecules of this substance are involved in the reaction |
| Nucleus | small, dense positively charged center of an atom |
| Subatomic Particle | proton, neutron, or electron |
| Proton | positively charged subatomic particle located in the nucleus of an atom |
| Atomic Mass Unit | unit used to measure the masses of subatomic particles |
| Neutron | subatomic particle with no charge located in the nucleus |
| Atomic Number | number of protons in the nucleus |
| Isotope | atom that has the same number of protons, but different number of neutrons |
| Mass Number | sum of the protons and neutrons in the nucleus |
| Atomic Mass | average of the masses of the existing isotopes of an element |
| Electron | negatively charged subatomic particle, found outside nucleus |
| Electron Cloud | space in which electrons are likely to be found |
| Energy Level | most likely location in an electron cloud in which an electron can be found |
| Electromagnetic Force | force of attraction of repulsion between particles |
| Strong Force | force that binds protons and neutrons |
| Weak Force | force that is the key to the power of the sun |
| Gravity | force of attraction that depends on the mass of two objects and the distance between them |
| Periodic Law | states that that the physical and chemical properites of the elements are periodic functions of their atomic numbers |
| Group | Vertical column in the periodic table |
| Family | Vertical column in the periodic table |
| Period | Horizontal row in the periodic table |
| Metal | element that is a good conductor of heat and electricity, shiny, high melting point, ductile and malleable, tends to lose electrons |
| Luster | shininess |
| Ductile | able to be drawn into a thin wire |
| Malleable | able to be hammered out into a thin sheet |
| Corrosion | gradual wearing away of a metal due to a chemical reaction in which the metal element is changed into a meallic compound |
| Nonmetal | element that is a poor conductor of heat and electricity, dull surface, low melting point, brittle, tends to gain electrons |
| Metalloid | element that has properties of both metals and nonmetals |
| Transition Metal | element that has properties similar to other transtition metals and to other metals but whose properties do not fit in with those of any other family |
| Boron Family | family 13 of the periodic table; elements have 3 valence electrons |
| Carbon Family | Family of 14; has 4 valence electrons |
| Nitrogen Family | family of 15; has 5 valence electrons |
| Oxygen Family | family of 16; has 6 valence electrons |
| Halogen Family | family of 17; has 7 valence electrons |
| Noble Gas | family of 18; has 8 valence electrons; extremely unreactive |
| Rare-Earth Element | lanthiloid and actinoid series |
| Chemical Bonding | combining of atoms of elements to form new substances |
| Valence Electron | electron in the outermost energy level |
| Ionic Bonding | bonding that involves the transfer of electrons |
| Ion | an atom that has become charged due to the loss or gain of electons |
| Ionization | process of removing electrons and forming ions |
| Crystal Lattice | regular, repeating arrangement |
| Covalent Bonding | bonding that involves the sharing of electrons |
| Electron Dot Diagram | diagram that uses tha chemical symbol for an element surrounded by a series of dots to represent the electron sharing that takes place in a covalent bond |
| Diatomic Element | element whose atoms can form covalent bonds with another atom of the same element |
| Molecule | combination of atoms formed by a covalent bond |
| Polyatomic Ion | group of covalently bonded atoms that acts like a single atom when combined |
| Metallic Bond | bond formed by atoms of metals, in which the outer electrons of the atoms form a common electron cloud |
| Oxidation Number | number of electrons an atom gains, loses, or shares, when it forms chemial bonds |
