Science Starter Give the name of the following compounds. 1. Na 3 N 2. V 2 S 3. Li 2 SO 4 Give the formula for the following compounds. 1. Potassium carbonate 2. Iron (IV) oxide 3. Sodium nitride
Objective SWBAT differentiate between ionic and covalent compounds SWBAT draw Lewis Dot Structures for covalent compounds SWBAT provide name given formula and provide formula given name for all covalent compounds
Agenda Science Starter Announcements Ionic or Covalent Practice Foldable: Covalent Name to Formula Formula to Name Practice/Homework
Announcements Today: Covalent Compounds Tuesday: Polarity and IMF Wednesday: Unit 3 Review Thursday: Unit 3 Test Friday: Intro to Unit 4
Ionic versus Covalent Ionic Compounds METALS and NONMETALS Covalent Molecules NONMETALS ONLY
Example Covalent or Ionic? Si 2 F 5
Example Covalent or Ionic? KF
Example Covalent or Ionic? F 3 Cl 5
Flash! Covalent or Ionic? NaCl
Flash! Covalent or Ionic? Dinitrogen pentaoxide
Web Quest: Covalent & Metallic Compounds Continue working with the Covalent Webquest You will have until 12:00pm to work on this, if you finish early put your laptop away and grab a sheet from the front Students are expected to be on task during this time! I will call people up for quiz grades and CIA #1
Covalent Bonds In forming covalent bonds, atoms share electrons to obtain the electron configurations of noble gases. (octet rule still applies!) EX: H 2
Anatomy of a Formula PBr 3 Subscript; tells you # of atoms of that element in the compound Element in the compound Element in the compound In this compound, there are three bromine atoms for every phosphorus atom.
Covalent Bonds Single covalent bond: two atoms held together by the sharing of two electrons Double covalent bond: sharing of four electrons Triple covalent bond: sharing of six electrons
Steps: Covalent Lewis Dot Structures 1) Count the total number of valence electrons (VE - ) 2) Pick the central atom (the single one) 3) Create a skeleton by putting a bond between central atom and outer atoms. 1 bond = 2 electrons! 4) Add remaining electron pairs to outside atoms first, then inner atoms. 5) If some atoms missing octet (8 VE - ), make double or triple bonds
Example: CF 4 1) Total valence electrons? 2) Central atom? 3) Skeleton 4) Remaining pairs 5) Octet happy?
Examples: Lewis Dots H 2 CO 2 Cl 2 O 2 CCl 4 N 2
Covalent Compounds Covalent compounds are made of two or more nonmetals bonded together. We use Greek prefixes to name covalent compounds.
Needed for Naming Covalent Compounds: Greek prefixes 1 = Mono 6 = Hexa 2 = Di 7 = Hepta 3 = Tri 8 = Octa 4 = Tetra 9 = Nona 5 = Penta 10 = Deca FOLDABLE! ***YOU MUST MEMORIZE THIS!!!
Covalent Compounds Going from the name to the formula: 1)Find the first element on the periodic table, and write down its symbol. If there is a prefix for the word, find its corresponding number from your table and place it AFTER THE SYMBOL! 2)Repeat with the second element in the compound and combine. (NO CHOP)
Example Ex: Tetrachlorineoctabromide 1. 2. Combine:
Covalent Compounds Going from a formula to its name: 1)Write out the first element fully. If there is a number after the element, put the corresponding greek prefix BEFORE THE WORD. 1)Write out the second element and end it with ide. If there is a number after the element, put the corresponding greek prefix BEFORE THE WORD.
Covalent Compounds 3) Combine the two words. Note: ONLY THE SECOND WORD IN A COMPOUND CAN START WITH MONO!!
Example Ex: S 2 O 3 1. 2. 3. Combine to
Example Ex: CO 1. 2. 3. Combine to
BrINClHOF EXCEPTION: BrINClHOF! Bromine, Iodine, nitrogen, chlorine, hydrogen, and oxygen are all diatomic molecules. Example: a) iodine b) N 2 c) oxygen d) Br 2
Diatomic Elements Diatomic Elements exist naturally with two atoms covalently bonded. F 2, Cl 2, Br 2, I 2, H 2, N 2, & O 2 7 Diatomic Elements: Diatomic elements form molecules because they are more stable bonded with another element. Not all of the diatomic s are single bonds, which ones are not? ANSWER: O2- double bond N2- triple bond
Work on the homework sheet and finish before class tomorrow!