CHEM102 1st Edition Lecture 2Outline of Last Lecture I. Went over Isotopes, their symbols, and how to write the symbolsII. The periodic table and how it is organized Outline of Current Lecture I. Chemical Bondsa. Ionic Bonding definitionb. Covalent Bonding DefinitionCurrent LectureChemical BondsChemical bonds: forces that hold the atoms together in substances Ionic Bonding: the transfer of electron from one atom to another Ex. Hydrogen giving it’s one valence electron to FluorineCovalent Bonding: the sharing of electrons between two atoms Ex. 2 Hydrogens sharing their valence electrons with Oxygen to form H2OValence Electrons: How many electrons are in the outermost shell; they interact with other atoms to do chemistry (See bottom of notes for a picture)*Each atom has “shells” around the nucleus containing a certain number of electrons. The first shell can only hold two electrons, the second can only hold 8, the third 16, etc.* *Every atom want to have 8 electrons in the outermost shell to become balanced like the noble gases, this is where ionic and covalent bonding come in. Exceptions to this include Hydrogen and Helium, which can only have two electrons maximum.*These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.*An atom can either get rid of, or gain electrons, depending on how many valence electrond they have. To find the number of valence electrons in a certain element, look at the numbers above the column. For example, Hydrogen has 1 valence electron because it is in column IA.* Elements in groups IA-IIIA get rid of their electrons Elements in group IVA can gain or lose 4 electrons Elements in groups VA-VIIIA can gain electronsLewis Dot-Electron Symbol: symbol for the element surrounded by dots, one for each electron (see bottom of noted for picture)*Cations of most representative elements done have valence shell electrons so you write these differently. EX. Instead of the Lewis Dot-Electron Symbol, write Na+**The elements you combine must be neutral! For example, instead of writing AlS, you write Al2S3. The charge of Al is +3 and the charge of S is -2. By switching the two charges, you can neutralize the bond. (See bottom of notes for Picture)*Ionic BondingIonic Bonding: results from the electrostatic attraction between cations and anions. This is viewed as a transfer of electrons. After an ionic bond is formed, the two atoms are stuck together forever. (See bottom of notes for picture example).*When salts give their electrons with metals, the metal always keeps its name and the salt ends with –ide. Ex. NaCl = Sodium Chloride*Covalent BondingCovalent Bonding: Atoms share electrons by overlapping orbitals * When drawing the Lewis Dot-electron Symbol for Covalent bonding, make sure each element has 8 electrons around it, excluding hydrogen and helium who only need 2.**In covalent bonding, there is a single bond when only one bond is formed at each intersecting orbital. There is also a double bond where one orbital has four electrons instead of two (See picture