Chemical Bonds -Textbook Notes

Chemical Bonds Chemistry of life Based on Carbon Compounds Depends on C that occur in aqueous environments Very Complex Coordinated by Collections of large polymers Element: Substances that Cannot be broken down or interconnected by Chemical means Atom: Smallest Still distinctive particle of an element Cells are made of relatively few types of atoms Atoms have a dense nucleus with a surrounding Cloud of electrons Nucleus Contains p+ and n° Atomic # is # of p+ and n° in the nucleus of e is equal to the # of p+ in a whole atom (electrically neutral) n° Contributes to Structural Stability Changed # can result in radioactive decay Isotopes: atoms of different # of n° * Multiple of most elements occur naturally Atomic Weight: Mass relative to the mass of a hydrogen atom * #p+ plus #n° * generally Specified in Daltons Avagadro #: 6x10^23, relates quantities of chemicals to # of atoms measured in moles (mol) Living Things: "Living things have C, H, N, and O make up 96% of their weight." Electrons: "Outermost e determine how Atoms interact." Electron Movement: "e are the accessible part." "In Continuous motion." "e can only exist in Certain discrete regions of movement." "limit to # that can be in each cell."   Electron Shells: "1st Shell = 2." "2nd +3rd = 8." "4th-5th = 18." Stability: "Most Stable when they occupy in the innermost shells." "Full outer Shell Chemically inert/unreactive." Reactions: "Atoms in living organisms aren't full so they can undergo reactions." "Incomplete Shells have strong tendency to interact." Ionic Bonds: "Ionic Bond: E donated from one atom to another." Covalent Bonds: "Covalent Bond: When two atoms Share a pair of e." Other Elements: "Other most common elements in living cells, C, N, O, P, S." Covalent Bond Formation: "Covalent Bonds Form by Sharing E." Molecule: "molecule Cluster of atoms held together by covalent bonds." Electron Cloud: "Shared e form a cloud that's derisest btwn 2 nuclei." "Helps to hold the nuclei togetter by opposing the mutual repulsion btwn the charges of the nuclei." Living Things: "Living things have C, H, N, and O make up 96% of their weight." Electrons: "Outermost e determine how Atoms interact." Electron Movement: "e are the accessible part." "In Continuous motion." "e can only exist in Certain discrete regions of movement." "limit to # that can be in each cell."   Electron Shells: "1st Shell = 2." "2nd +3rd = 8." "4th-5th = 18." Stability: "Most Stable when they occupy in the innermost shells." "Full outer Shell Chemically inert/unreactive." Reactions: "Atoms in living organisms aren't full so they can undergo reactions." "Incomplete Shells have strong tendency to interact." Ionic Bonds: "Ionic Bond: E donated from one atom to another." Covalent Bonds: "Covalent Bond: When two atoms Share a pair of e." Other Elements: "Other most common elements in living cells, C, N, O, P, S." Covalent Bond Formation: "Covalent Bonds Form by Sharing E." Molecule: "molecule Cluster of atoms held together by covalent bonds." Electron Cloud: "Shared e form a cloud that's derisest btwn 2 nuclei." "Helps to hold the nuclei togetter by opposing the mutual repulsion btwn the charges of the nuclei." Bond Length: "Bond Length: Characteristic distance nuclei are separated when attractive + repulsive forces are in balance." Covalent Bonds with Multiple Electron Pairs: "Single Bond: 2 electrons are shared, 1 donated by each atom." "Double Bond: 4 electrons are shared, 2 donated by each atom." "Have a characteristic effect on geometry of molecules." "Prevent rotation around bond axis, impacting 3-D Shape." "Produces a more rigid and less flexible arrangement of atoms." Electrons in Covalent Bonds: "Electrons in Covalent Bonds are often shared unequally." Polar Covalent Bonds: "Polar e are shared unequally." "Charge is toward one atom. Charge to the other (δ+ δ- poles)." Electronegativity: "Electronegativity: tendency of an atom to attract e-." Polarized Bonds: "Atoms with different electronegativities are covalently linked, and the bonds will become POLARIZED."