Chapters 7-9: Chemical Composition Intra-chemical Forces Intra = within Atoms (elements) held together by an attractive force Metallic Bonding atoms of a metal share the valence electrons because they move from one element to another
Ionic Bonding valence electrons are transferred between two elements strongest bonds Covalent Bonding valence electrons
are shared between two elements Weaker bonds than ionic bonds Ionic Bonding Electrons are transferred from one element to another.
Ionic Bonding Opposite charges is attractive force Commonly referred to as salts Atoms that donates electron = cation Atom that accepts electron = anion Oxidation state refers to the charge of an atom
Lewis Dot Formulas Octet Rule: every element wants 8 electrons in its outer shell. a) potassium + chlorine potassium chloride b) magnesium + fluorine magnesium fluoride Types of Ions
monatomic cation: cation with one element K+ Mg2+ Fe3+ Fe2+ Mn7+ Au3+ Au+ monatomic anion: anion with one element name ends in ide Cl O2 N3 S2
F P3 Br polyatomic ion: many atoms covalently bonded that have a net charge. NO3 SO42 C2H3O2 PO43 NH4+
Writing Ionic Chemical Formulas 1. 2. 3. 4. 5. 6. Composition number of elements Writing chemical formulas (from the names)
Recognize the (+) and () ions Write the symbols of the elements with their charge A Roman numeral will tell you what the charge is on the cation if there is more than one possibility 7. Adjust the number of each ion (with subscripts) as needed so the positive charge is equal and opposite the negative charge. 8. If the ions are polyatomic and there is more than one, the ion is enclosed with parentheses with a subscript on the outside.
Writing Ionic Chemical Formulas 1. sodium chloride 2. calcium sulfide 3. calcium sulfate 4. barium phosphate Naming Ionic Compounds a) Consists of two words:
b) Name the cation c) Name the anion d) If the cation has more than one possible charge, a Roman Numeral is used to show the charge. e) All transition metals need roman numerals except: i. Zinc always has a charge of +2 ii. Silver always has a charge of +1 Naming Ionic Compounds
1. FeCl3 Fe3+ iron(III) chloride 2. FeCl2 Fe2+ iron(II) chloride 3. NH4Cl 4. Cu2SO4 5. NaC2H3O2
6. Ca(NO3)2 7. Zn(ClO)2 8. Cu2O Naming Ionic Compounds 1. FeCl3 Fe3+ iron(III) chloride 2. FeCl2
Fe2+ iron(II) chloride 3. NH4Cl ammonium chloride 4. Cu2SO4 copper (I) sulfate 5. NaC2H3O2
sodium acetate 6. Ca(NO3)2 calcium nitrate 7. Zn(ClO)2 zinc hypochlorite
8. Cu2O copper (I) oxide Covalent Bonding A.Valence electrons are shared between two elements B.Weaker than ionic bonding polar & nonpolar covalent bonds Polar Covalent (stronger): unequal
sharing of electrons (the more electronegative element pulls more) Nonpolar Covalent (weaker): equal sharing of electrons Writing Formulas for Covalent Compounds 1. carbon dioxide 2. carbon monoxide 3. dinitrogen monoxide 4. carbon tetrafluoride
5. triphosphorus pentachloride Naming Formulas for Covalent Compounds Binary covalent compounds (2 elements) Formulas with two nonmetals Rules: i. First word: 1. prefix indicating the number of atoms for the first element (if there is more than one) 2. name of first element
ii. Second word: 1. prefix for the number of atoms of the second element (prefixes on supplement notes sheet) 2. name of second element 3. suffix ide Naming Formulas for Covalent Compounds 1. NO 2. NO2 3. CBr4
4. P4O10 5. BF3 6. SiI5 7. H2O 8. S6Cl8 Naming Formulas for Covalent Compounds 1. NO 2. NO2
nitrogen monoxide nitrogen dioxide 3. CBr4 carbon tetrabromide 4. P4O10 tetraphosphorus decoxide
5. BF3 boron trifluoride 6. SiI5 silicon pentaiodide 7. H2O dihydrogen monoxide
8. S6Cl8 hexasulfur octochloride Lewis Structures The number of covalent bonds formed by an atom equals the number of unpaired electrons in the Lewis Dot Formula. i. water (H2O)
Lewis Structures ii. Hydrogen gas (H2) iii. Hydrochloric acid (HCl) Lewis Structures iv. ammonia (NH3) v. methane (CH4) Multiple Bonds
i. double bonds: two pairs of electrons shared O2 ii. triple bonds: three pairs of electrons shared N2 Hybridization Combining of two or more orbitals of nearly the same energy into new orbitals of equal energy
Hybridization Most common hybridizations occur in groups 2, 13, 14 (IIA, IIIA, IVA) Group 2 (IIA): Beryllium: [He]2s2 sp hybrid Hybridization Most common hybridizations occur in groups 2, 13, 14 (IIA,
IIIA, IVA) Group 13 (IIIA): Boron: [He]2s22p1 sp2 hybrid Hybridization Most common hybridizations occur in groups 2, 13, 14 (IIA, IIIA, IVA)
Group 14 (IVA): Carbon: [He]2s22p2 sp3 hybrid Molecular Polarity Molecules with more than one element (polar or nonpolar) depends on: i. electronegativity
difference (2 elements) ii. Non-bonded electron pairs (2+ elements) Inter-chemical forces A. Inter = between B. Whole salts or molecules attract and bond with one another
Inter-chemical forces 1. Ion dipole 2. Hydrogen Bonding 1. Dipole Dipole 2. London Dispersion Ion Dipole forces
Strongest interchemical force hydrogen bonding hydrogen bonding is a unique case of dipole dipole bonding occurs because hydrogens
exposed proton results in a slight hydrogen bonding medium strength inter-chemical bond. occurs in molecules when hydrogen is bonded with F, O, or N.
hydrogen bonding hydrogen bonding is responsible for: waters high boiling point, and the low density of ice
dipole dipole bonding weaker than hydrogen bonding. occurs between polar molecules London Dispersion Forces named after Fritz London the weakest intermolecular force the random movement of electrons can
create an instantaneous dipoles
