Chapter 2 vocab terms, all are from the AP Edition of Campell Biology, 9th edition
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| 838711247 | matter | anything that takes up space and has mass | |
| 838711248 | element | substance that cannot be broken down to other substances by chemical reactions | |
| 838711249 | compound | substance consisting of two or more different elements combined in a fixed ratio | |
| 838711250 | essential elements | 20-25% of the natural elements, elements that are necessary to an organism to live a healthy life and reproduce | |
| 838711251 | trace elements | required by an organism in only minute quantities, some are required by all forms of life (ex FE), others are only required by certain species | |
| 838711252 | atom | the smallest unit of matter that still retains the properties of an element | |
| 838711253 | neutrons | a subatomic particle having no electrical charge (electrically neutral) with a mass of about 1.7 x 10^-24g, found in the nucleus of an atom | |
| 838711254 | protons | a subatomic particle with a single positive charge, with a mass of about 1.7 x 10^-24g, found in the nucleus of an atom | |
| 838711255 | electrons | a subatomic particle with a single negative electrical charge and a mass about 1/2,000 that of a neutron or proton. One or more elections move around the nucleus of an atom | |
| 838711256 | atomic nucleus | a dense core at the center of an atom | |
| 838711257 | dalton | a measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu | |
| 838711258 | atomic number | the number of protons in an element, each of which is unique to an element that is written as a subscript to the left of the symbol for the element | |
| 838711259 | mass number | sum of protons plus neutrons in the nucleus of an atom. The mass number is written as a superscript to the left of an element's symbol | |
| 838711260 | atomic mass | the total mass of an atom | |
| 838711261 | isotopes | different atomic forms of the same element | |
| 838711262 | radioactive isotope | an isotope in which the nucleus decays spontaneously, giving off particles and energy | |
| 838711263 | energy | the capacity to cause change-for instance by doing work | |
| 838711264 | potential energy | the energy that matter possesses because of its location or structure | |
| 838711265 | electron shell | an energy level of electrons at a characteristic average distance from the nucleus of an atom | |
| 838711266 | valence electron | an electron in the outermost electron shell | |
| 838711267 | valence shell | the outermost energy shell of a given atom, containing the valence electrons involved in the chemical reactions of that atom | |
| 838711268 | orbital | the space in which an electron spends most of its time, the three dimensional space where it is found 90% of the time | |
| 838711269 | chemical bond | an attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells | |
| 838711270 | covalent bond | the sharing of a pair of valence electrons by two atoms | |
| 838711271 | molecule | two or more atoms held together by covalent bonds | |
| 838711272 | single bond | a pair of shared electrons | |
| 838711273 | double bond | a bond formed by the sharing of two pairs of valence electrons | |
| 838711274 | valence | the bonding capacity of an atom | |
| 838711275 | electronegativity | the attraction of a particular atom for the electrons of a covalent bond | |
| 838711276 | nonpolar covalent bond | a type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity | |
| 838711277 | polar covalent bond | a covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive. | |
| 838711278 | ion | a charged atom (or molecule) | |
| 838711279 | cation | an ion with a positive charge | |
| 838711280 | anion | a negatively charged ion | |
| 838711281 | ionic bond | the attraction between cations and anions, because of their opposite charges | |
| 838711282 | ionic compounds | compounds formed by ionic bonds, also known as salts | |
| 838711283 | hydrogen bond | the noncovalent attraction between a hydrogen and an electronegative atom | |
| 838711284 | van der Waals interactions | weak attractions between molecules or parts of molecules that result from transient local partial changes | |
| 838711285 | reactants | starting materials of a chemical reaction | |
| 838711286 | products | the ending products of a chemical reaction | |
| 838711287 | chemical equilibrium | the point at which reactions offset one another exactly |
