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Chemical Bonds. attractive force that holds atoms together in a compound. Valence electrons - determines bonding ability. Electrons in outermost energy level- 1, 2, 3, 4, 5, 6, 7, 8. Octet Rule - Atoms attempt to acquire an outer shell(orbital) with 8 electrons. Bonds. Ionic. Covalent.
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Chemical Bonds • attractive force that holds atoms together in a compound. • Valence electrons - determines bonding ability. Electrons in outermost energy level- 1, 2, 3, 4, 5, 6, 7, 8. • Octet Rule - Atoms attempt to acquire an outer shell(orbital) with 8 electrons.
Bonds Ionic Covalent Metallic Chemical Bonds
Ionic Bonds • between a metal & non-metal • forms ions (charged atom + or --) by transferring e- • one atom gains e- (neg. ion), the other atom loses e- (positive ion). • Opposites attract!
Ionic Bonds • Ionization - the process of removing an e- and forming ions. • Ionization energy - energy needed for removing an e- and forming ions. ( valence e- have I.E.). • Electron affinity - tendency of an atom to attract e- (halogens e- affinity). • Crystal lattice - huge # of ions grouped in a regular repeating pattern. Great stability. Ex. NaCl
Covalent Bonds • between non-metals • forms molecules by sharing electrons • H2O molecule
Covalent Bonds • Diatomic elements - atoms of the same element bonded together. Ex. H, N, O, F, Cl, Br, I. • Single vs. Multiple Bonds
Metallic Bonds • between metals • made up of a “Sea of Electrons” - mobile e- yet attracted to nuclei. Accounts for malleability, ductility, electricity. • Forms a metallic crystal - outer e- of atoms form e- cloud.
Chemical Bonds Review NaCl CaF2 Metal - Nonmetal Transfer of e- H2O CO2 Nonmetals Sharing e- Fe Cu Metals “Sea of e-”
Writing Chemical Formulas • A chemical formula shows the ratio of atoms used to make the compound. • 2 iron, 3 oxygen = Fe2O3 • 6 carbon, 12 hydrogen, 6 oxygen = C6H12O6 • 2 hydrogen, 2 oxygen = H2O2 • 1 nitrogen, 3 hydrogen = NH3
Oxidation Numbers • Ion charge • predicts how atoms will combine & what the formula for the resulting compound will be. • # of e- an atom gains, loses or shares when it forms chemical bonds. • Must equal 0.
Polyatomic Ions • group of covalent bonded atoms that act like a single ionic atom that combines with other atoms. • NH4+1 ammonium NO3-1 nitrate • C2H3O2-1 acetate NO2-1 nitrite • ClO3-1 chlorate CO3-2 carbonate • HCO3-1 bicarbonate SO4-2 sulfate • OH-1 hydroxide SO3-2 sulfite • PO4-3 phosphate
Naming Binary Ionic Compounds • Compounds made of only two different elements. • Rules: - Write positive ion first. • - If transition metal, determine ox. #. Use roman numerals in parentheses after ions name. • - Write root name of the negative ion, add • suffix –ide to it. • Examples: NaCl - Sodium Chloride • HS - Hydrogen Sulfide • FeO - Iron (II) Oxide
Binary Ionic Compounds • Examples of negative ion suffixes: • hydrogen - hydride oxygen - oxide • nitrogen - nitride fluorine - fluoride • phosphorus - phosphide chlorine - chloride • bromine - bromide iodine - iodide • sulfur – sulfide
Uses prefixes. Examples: N2O dinitrogen oxide NO nitrogen oxide NO2 nitrogen dioxide N2O5 dinitrogen pentoxide Binary Covalent Compounds