| A | B |
|---|
| Atom | The smallest particle of an element. |
| Nucleus | Dense, positively charged mass at the center of an atom. |
| Proton | Positively charged subatomic particle found in the nucleus. |
| Neutron | Neutral subatomic particle found in the nucleus. |
| Electron | Negatively charged subatomic particle found outside the nucleus. |
| Mass number | The sum of the protons and neutrons in the nucleus of an atom. |
| Atomic number | This number identifies the element and is equal to the number of protons found in the nucleus. |
| Ion | An atom with a charge (unequal number of protons and electrons) |
| Isotopes | Versions of the same element with different numbers of neutrons. |
| Energy levels | The possible energies that an electron in an atom can have. |
| Atomic Weight/Mass | The weighted average mass of all of an element's isotopes' mass numbers (usually a decimal). |
| Electron Cloud | A visual model showing the most likely locations for the electrons in an atom. |
| Electron configuration | The arrangement of electrons around the nucleus of an atom. |
| Ground state | When all of the electrons in an atom have their lowest possible energies. |
| matter | anything that has mass and takes up space |
| mass | the amount of matter in an object |
| volume | the amount of space an object takes up |
| pure substance | matter that always has the exact same composition |
| fixed composition | always made up of the same elements (or element) in the same ratio |
| heterogeneous | made up of different materials that can be distinguished, or identified, by sight |
| homogeneous | made up of materials that cannot be distinguished by sight; may be either different materials or the same |
| element | a substance that cannot be broken down into simpler substances |
| compound | a substance that is made up of two or more simpler substances and can be broken down into those simpler substances |
| mixture | a substance made up of more than one material but not in a fixed ratio |
| solution | a homogeneous mixture |
| suspension | a heterogeneous mixture that separates into layers over time |
| filtration | a process that separates materials based on the size of their particles |
| distillation | a process that separates the substances in a solution based on their boiling points |
| desalination | the process of removing salt from water |
| molecular model | a model showing the arrangement of atoms in a molecule or multiple molecules |
| soluble | able to be dissolved. Example: salt in water |
| insoluble | unable to be dissolved. Example: sand in water |
| solute | material being dissolved |
| solvent | the liquid in which a solute is dissolved to form a solution |
| atom | the smallest unit of an element |
| molecule | a group of atoms that are joined, or bonded, together |
| element | a substance that contains only one kind of atom |
| compound | a substance made up of two or more simpler substances that are chemically combined |
| chemical formula | a notation that shows what elements a compound or molecule contains |
| coefficient | the number of atoms or molecules of whatever follows it |
| subscript | show the number of atoms of the element to its left; used in molecules |
| chemical equation | a written form of what happens in a chemical reaction |
| reactants | the substances that react together in a chemical equation; always on the left side of a chemical equation |
| products | the subststances that are produced from a chemical reaction; always on the right side of a chemical equation |
| Law of Conservation of Mass | Matter (or mass) can neither be created nor destroyed in a chemical reaction |
| ionic bond | a chemical bond in which electrons are transferred from one atom to another |
| covalent bond | a chemical bond in which electrons are shared between atoms |
| valence electrons | electrons in an atoms outermost energy level; responsible for chemical bonding |
| octet rule | atoms tend to combine in ways that result in their valence shells (outer energy level) filled with 8 electrons |
| lattice structure | arrangement of atoms in ionic compounds |
| matter | anything that takes has mass and takes up space |
| significant figures | any digit of a number that is known with certainty |
| Kinetic Particle Theory of Matter | states that all matter is made up of moving particles that are constantly moving |
| kinetic energy | energy that results from motion |
| mass | the amount of matter in an object |
| water displacement | a method of finding the volume of an irregularly shaped object |
| metric prefix | the first part of a metric number; determines the multiplier that is used for the unit |
| kilo- | a metric prefix meaning 1000x |
| centi- | a metric prefix meaning 1/100th or .01 |
| milli- | a metrix prefix meaning 1/1000th or .001 |
| base (or unit) | the unit of measure being used (meter, liter or gram); represents a prefix of 1x |
| physical property | any characteristic of a material that can be observed or measured without changing the composition of the substances in the material |
| chemical property | a property that is observed only when a substance is changing from one substance to another |
| viscosity | the resistance of a liquid to flowing |
| conductivity | the resistance of a material to electrical current |
| malleability | ability of a solid to be hammered without shattering |
| melting point | The temperature at which a substance changes from a solid to a liquid |
| density | the ratio of an objects mass to its volume |
| flammability | a material's ability to burn in the presence of oxygen |
| reactivity | how readily a substance combines with other substances |
| precipitate | a solid substance that forms when two chemicals are mixed together |
| exothermic | a reaction that releases energy |
| endothermic | a reaction that absorbs energy |
| toxicity | the degree to which a substance can damage an organism |
