Unit 5: Chemical bonding, names and formulas Ch. 7 & 8 7.1 Ions and Ionic Compounds I. Define Ion NAME Period: A. Lewis Dots and Valence electrons: Uses to represent B. Rule: Every atom wants a valence shell (usually e s) C. Cations are because they have electrons. form these positive ions. D. Anions are because they have electrons. form these negative ions. E. We ll draw electron orbital diagrams and lewis dots to illustrate how this happens. 1. sodium atom to sodium ion: 2. chlorine atom to chloride ion: 7.2 Ionic Bonds: Bond formed due to charges of. A. What type of bond will form with sodium and chlorine after they become ions?
1. Show a magnesium atom forming an ionic bond with potassium using electron orbital diagrams: B. How do we name positive ions? C. How do we name negative ions? D. Units: Simply enjoy your new ability to get away with saying Mr. Glane, a metal and a non-metal make a salt called a 1. These are also commonly called compounds because they are made of metal with charges and non-metal with charges 2. Always made of and. 3. They do not exist at singular like molecules. Instead they are a crystalline with a repeating. The formula you write represents the of metal ions to. a. Sodium Chloride is NaCl. So.. b. The grid is hard to break, so ionic compounds are hard to. This rigidity also makes them when hit. Practice Problems 1. How many ions of each element are in an ionic compound made from magnesium and phosphorus? 2. How many ions of each element would be in the formula unit for aluminum and oxygen bonding?
3. Why are these salts called Formula Units? Because the represents the smallest that perfectly the ratio of to in the structure. 7.3 Metallic Bonds: Since metals have low, they easily electrons. Because of this quality, they tend to exist as positive with free- electrons. This is often referred to as a of electrons. A. Properties like,, are explained by this sea of free-floating electrons. B. Metals form close packed formations called structures. These are very which explains the high of most metals. C. Metal : These are mixtures of metals that are together. They all behave so that they easily share 8.1 Representing Molecular Compounds A. Formulas show the and of atoms in a. That means all which are bonded into a single unit, or compound. B. The bond type is called a bond because they are valence electrons since they both want to. i. The written the element symbol indicate the number of of each element in the molecular compound. ii. If there is only atom of an element, number is used.
iii. The molecular formula represents the smallest unit of the substance. The particle is called a which is a group of, electrons. Water s molecular formula is, so the molecule is.. iv. Molecules do exist as entities. Since they are not and, each molecule is of the other molecules nearby. Therefore, they often have melting and boiling points because each individual is easy moved away from others. v. The large numbers in front of the chemical formula, called coefficients, show the So 3 H 2 O C. There are 7 diatomic molecules in nature. They are,,,,,,. Diatomic means. 8.2 The nature of covalent bonding A. Define a single covalent bond: Sharing pair of electrons. Using Lewis Dot Structures to draw covalent bond. 1. Sum the valence electrons 2. Write the symbols for the atoms to show which atoms are attached to which, and connect them with a single bond. Think symmetry by picking any central atoms! 3. Complete the octets around all the atoms bonded to the central atom. (Remember hydrogen obeys the duet rule, all other atoms obey the octet rule.) 4. Place any leftover electrons on the central atom (even if doing so results in more than an octet) 5. If there are not enough electrons to give the central atom an octet, try moving electron pairs from outer atoms to make double, or triple bonds with the central atom. 6. Draw a line instead of a pair of electron dots to represent the covalent bond formed.
Using Electron Configurations and Orbital Diagrams to show covalent bonds. 1. Draw shorthand electron configs & diagrams for all the non-metals in the compound. *Stagger the diagrams if possible, only write out one configuration per element. 2. Circle the shared valance electrons between all your non metals using long ovals. 3. Make sure shared electrons have opposite spins (arrow directions). 1. Show the covalent bond(s) in a Fluorine molecule, F 2, using 2. Show the covalent bond(s) in an ammonia molecule, NH 3, using 3. Show the covalent bond(s) in a Fluorine molecule, H 2 O, using 4. Show the covalent bond(s) in a Fluorine molecule, CH 4, using B. Define double covalent bonds: Sharing pairs of electrons. C. Define triple covalent bonds: Sharing pairs of electrons.
5. Show the covalent bond(s) in an oxygen molecule, O 2 using 6. Show the covalent bond(s) in a nitrogen molecule, N 2,using 7. Show the covalent bond(s) in a silicon dioxide molecule, SiO 2, using 8. Show the covalent bond(s) in a dinitrogen dihydrogen molecule, N 2 H 2,using D. Define Coordinate Covalent Bonds: a covalent bond in which one atom contributes electrons 9. Show the coordinate covalent bond within carbon monoxide E. Bond energy is the energy needed to the covalent bond between. F. Resonance: When electrons can around a molecule to be in ways.
10. Draw the resonance structure for Ozone, O 3 8.3 Bonding Theories 16.1 VESPR Theory 1. dimensional models of molecules depend on a. The of covalent bonds b. The types (,, ) of bonds c. The number of electrons on the atom. 2. The basis of molecular geometry is that pairs of electrons want to be as as possible from each other Shapes of Molecules # of Central Bond areas # unshared electrons Diagram Tetrahedral Trigonal Planer Linear Triatomic Pyramidal Bent Linear Diatomic
a. and bonds act like bond area each. b. Some molecules have multiple atoms 3. Bond Classification:,, or a. Determined by which is the tendency to electrons Electronegativity Differences and Bond Types Electronegativity Most probable type of bond Example difference Range b. Ionic Bonds: When the difference between bonding elements is very resulting in the highly electronegative element (non-metal), while the weakly electronegative element (metal). Difference = c. Non-Polar Covalent: The elements have very electronegativity so they share. Difference= H 2 d. Polar-Covalent: The elements in the bond have electronegative differences between. HCl e. Attractions between molecules called i. Vanderwall forces ii. Dipole interactions 1. Hydrogen Bonding (Water, and -O-H groups ) b. Some polar bonds do not result in polar molecules if the structure is. ie: CO 2