CLEP Biology Study Guide 2023/2024

Matter --Any substance that occupies space and has mass Elements --Unique forms of matter with specific chemical and physical properties that cannot be broken down into smaller substances by ordinary chemical reactions Chemical Symbol --A single capital letter, or when the first letter is already "taken" by another element, a combination of two letters. Some elements follow the English term for the element, other elements chemical symbol derive from their Latin names Natural Elements --92 Total Elements --118 Atom --The smallest unit of matter that retains all of the chemical properties of an element Nucleus --The center of an atom and contains protons and neutrons Electrons --The Negative part of the atom that orbits around the nucleus Atomic Mass --the mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes. Atomic Number --The number of protons determins an element's atomic number and is used to distinguish one element from another. Isotopes --Atoms that have the same number of protons but a different number of neutrons. Radioisotopes --unstable isotopes that emit radiation and decay into other isotopes Periodic Table --A table of elements that are organized and displayed according to their atomic numbers and are arranged in a series of rows and columns based on shared chemical and physical properties. In addition to providing the atomic number for each element, the periodic table also displays the element's atomic mass. The periodic table shows the atomic mass and the atomic number of each element. The atomic number apperars above the symbol for the element and the approximate mass appears below it. The periodic table is arraganged in columns and rows based on the number of electronsand where these electrons are located. Chemical Reactivity --The ability to combine and to chemically bond with each other. Molecules --Are simply two or more atoms chemically bonded together. Electrically Neutral Atoms --The number of electrons is the same as the number of protons. Thus, each element, at least when electrically neutral, has a characteristic number of electrons equal to its atomic number. Bohr Model -- Octect Rule --With the exception of the innermost shell, that atomsare morestable energetically when they have eight electrons in thier valence shell Valence Shell --The outermost electron shell Ions --An atom or molecule with a net electric charge due to the loss or gain of one or more electrons. Shell --Obit that the electorns follow Orbitals --Regions with in an atom that an electron would most likely occupy. Subshells (s,p,d, and f) --Maxium number of electrons: S = 2, P = 6, D = 10, and F = 14 Reactants --Substances used in the beginning of a chemical reaction. Products --Substances found at the end of the reaction. Law of Conservative Matter --The number of atoms before and after a chemical reactions should be equal, such that no atoms are, (under normal circumstances), created or destroyed. Balanced Chemical Equation --Wherein the number of atoms of each element is the same on each side of the equation Irreversable Reactions --The equation that proceeds in one direction until the reactants are all used up Macromolecules --a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer. Organic Molecules --Any molecule containing carbon Covalent Bonds --Bonds created by sharing electrons with other atoms. Hydrocarbons --Organic molecules consisting enterly of carbon and hydrogen