Unit one: The Chemistry of Life
Chapter 2: The Chemical Context of life
Terms : Hide Images
| 7300437440 | Element | Substance that cannot be broken down to other substances through chemical reactions. Each has a symbol. 92 occurring in nature. |  | 0 |
| 7300437441 | Compound | Substance consisting of two or more different elements combined in a fixed ratio. *Characteristics different than those of its elements |  | 1 |
| 7300437442 | CHON | 4 elements essential to life | 2 | |
| 7300437443 | Trace Elements | Required by an organism only in minute quantities. | 3 | |
| 7300437444 | Atom | Smallest unit of matter that retains the properties of an element. Composed of subatomic particles. Mostly empty space. | 4 | |
| 7300437445 | Subatomic particles | Neutrons, protons, electrons. Make up atoms. | 5 | |
| 7300437446 | Proton | One unit of positive charge. Approximately one dalton. Located in nucleus. |  | 6 |
| 7300437447 | Electron | One unit of negative charge. Located outside of nucleus. | | 7 |
| 7300437448 | Atomic Nucleus | Dense core packed with protons and neutrons. |  | 8 |
| 7300437449 | Neutrons | Electrically neutral. Approximately one dalton. |  | 9 |
| 7300437458 | Electron Shells | Where electrons are found, each with characteristic average distance and energy level. Electrons can change these by absorbing or losing energy. |  | 10 |
| 7300437459 | Valence Electrons | Electrons in the outermost shell. |  | 11 |
| 7300437463 | Chemical Bonds | The attraction that holds atoms together during an interaction. | 12 | |
| 7300437464 | Covalent Bond | Sharing of a pair of valence electrons by two atoms. |  | 13 |
| 7300437465 | Molecule | Two or more atoms held together by covalent bonds. | 14 | |
| 7300437466 | Single Bond | One pair of shared electrons. | 15 | |
| 7300437469 | Double Bond | Sharing two pairs of valence electrons. | 16 | |
| 7300437471 | Electronegativity | The attraction of a particular kind of atom for the electrons of a covalent bond. |  | 17 |
| 7300437472 | Nonpolar Covalent Bond | Covalent bond in which electrons are shared equally. |  | 18 |
| 7300437473 | Polar Covalent Bond | Where one atom is bonded to a more electronegative atom and the electrons of the bond are not shared equally. |  | 19 |
| 7300437474 | Ionic Bonds | The attraction of cations and anions. The transfer of electrons creates ions which form an ionic bond. |  | 20 |
| 7300437475 | Ion | A charged atom. | 21 | |
| 7300437478 | Ionic Compounds | Or Salts. Compounds formed by ionic bonds. |  | 22 |
| 7300437479 | Hydrogen Bond | When a hydrogen atom covalently bonded to an electronegative atom is also attracted to another electronegative atom. |  | 23 |
| 7300437482 | Reactants | The starting materials of a chemical reaction. |  | 24 |
| 7300437483 | Products | The resulting material of a chemical reaction. | | 25 |
| 7300437484 | Chemical Equilibrium | The point at which the relative concentrations of the products and the reactants stop changing and offset one another exactly. |  | 26 |
