Chapter 7 Compounds
Test corrections -done on a separate piece of paper -show your work (not just m/c letters!) -staple corrections sheet to your original test, and place in the hand-in bin :)
Lab Reports black or blue ink! 1 mark: headings title, name, date, partner underlined with ruler 1 mark: purpose in your own words 1 mark: procedure 4 marks: observations data table? graph? 5 marks: questions complete sentences 2 marks: conclusions Should include a discussion of results and errors 1 mark: neatness no scribbles: single x-out Total: 15 marks
The Perfect Graph! Title Labelled axes Appropriate scale Best fit line (do not connect the dots) Slope calculations Correctly chosen dependent/ independent variables Displacement /m Displacement vs. time m = Time /s Δy Δx = y x 2 2 y x 1 1
Lab Prep Lab 6A Purpose: to separate elements from a compound Procedure: refer to text, p. 162-3 Observations: Observations Procedure Step 5 Name Date Block Partner 8 9
Lab Prep Design Lab Purpose: to see how density depends on salt added to water Procedure: Step 1: measure 100 ml water Step 2: add 10 grams salt... Observations: Observations Procedure Step 5 Name Date Block Partner
Questions: 1. Answer all questions in complete sentences 2. Challenges may be done for extra marks, but are not mandatory Conclusions: State the most important finding of the lab. List any sources of error and potential improvements you might make next time
Compounds are combinations of more than one element These always have a fixed ratio for a particular compound
Bohr Diagrams We tend to see ions where atoms can give or take a few electrons to get full outer, or valence shell He 2p 2n number of electrons in outer shell = 2
Li 3p 4n Be 4p 5n number of electrons in outer shell = 1 number of electrons in outer shell = 2
Lithium ion? Li 3p 4n Li 3p 4n number of electrons in outer shell = 1 number of electrons in outer shell = 0
Fluorine ion F 9p 10n F 9p 10n number of electrons in outer shell = 7 number of electrons in outer shell = 8
Ex: write the formula then draw a Bohr model for nitrogen trichloride
Bohr Theory and Reactivity All atoms want either a full, or empty valence shell Just one electron? Kick it out!
All atoms want to be like a noble gas
Forming Ions Atoms take the easiest route to get a full outer shell. Here are examples: Mg Mg It will lose 2 electrons to get a full outer shell. Atom Mg Ion Mg +2 F F Atom F (short 1 e- of a full shell) Ion F-
The Rule! Losing electrons makes a positive ion. Eg: Mn 2+ Na + Gaining electrons makes it a negative ion. Eg: I - O 2-
Bohr Diagram of Ions Bohr Model of N 3- N Bohr Model of Na + + Na This minus means it has 3 extra electrons. -3 N3-7 N -3 14 The plus means it s missing an electron. Na + = only 10 electrons.
Try this: Fill in the blanks. Ion 15 P 1 e + 1 18 - Net charge = Symbol Do Pg. 174 #s 1-6,10-12
Ionic vs Covalent compounds
Ionic Compounds Formed from a metal and a non metal The metal gives up electrons The non metal takes electrons Tend to form rigid crystals
Covalent Compounds Formed from non metals The non metals share electrons Tend to form molecules
Check your understanding P. 182 q's 2-10 even numbers
Lab 6A conclusion Summarize the most important discoveries or results of the lab. Any limitattons or possible improvements?
Ch 7 quiz 1 1. A 2. D 3. D 4. B 5. D 6. B SA1 element: only one kind of atom, can't be broken down chemically. Compound: more than one element SA2 hard, brittle crystals. High melting points, conduct electricity when dissolved in water
Chemical Formulae Instead of writing out the whole name of a compound, we can use symbols e.g. sodium chloride: NaCl calcium oxide: CaO Atoms of the same or different element can bind together in bunches called molecules. e.g. molecule of an element: oxygen molecule: O 2 ozone molecule: O 3 molecule of a compound: carbon dioxide: CO 2
What do the numbers mean? The subscript number to the RIGHT of the symbol tells you how many of each there are: ex: Aluminum oxide Al 2 O 3 means: 2 aluminum for every 3 oxygen What if there is no number? This means only one of this element ex: magnesium chloride MgCl 2 means: 2 chlorine for every one magnesium calcium oxide: CaO means: one of each
Radicals These are groups of elements that behave like one atom Also called polyatomic ions For example CaCO 3 is called: calcium carbonate Notice we don t change the name of the radical in the chemical name Ex 2: Mg(OH) 2 is: magnesium hydroxide
How do we make a formula? Each element has its own ion charge Ramses II had over 100 children!!
Kris-Kross?
The number of atoms of each element must be adjusted to find a common denominator Criss-cross Applesauce! Ex 1: hydrogen and oxygen H 1 O 2 H 2 O 1 or simply H 2 O
Ex 2: calcium and chlorine Ca 2 Cl 1 Ca 1 Cl 2 or simply CaCl 2 Ex 3: aluminum and oxygen Al 3 O 2 Al 2 O 3
Multiple personality disorder? Some elements have more than one possible combining capacity These will have Roman numerals in the name so you know which to use Ex 1: copper (I) oxide would be: Cu 1 O 2 Cu 2 O 2 Cu 2 O Ex 2: copper (II) oxide would be: Cu 2 O 2 CuO
We still do criss-cross applesauce for radicals Ex 2: calcium and chlorite Ca 2 ClO 2 1 Ca(ClO 2 ) 2 Ex 3: aluminum and sulphate Al 3 SO 4 2 Al 2 ( SO 4 ) 3
How do we name an ionic compound? Most compounds are a combination of a metal and non-metal (opposites attract) When we name a compound we write: the name of the metal first, then the name of the non-metal, with the ending of her name changed to -ide Ex 1: lithium + chlorine lithium chloride Ex 2: calcium + fluorine calcium fluoride
Reverse Criss Cross? How do we know which CC we have? Given the formula we can write the name. Mn 2 Cl 1 Ex: MnCl 2 So the name would be: manganese(ii)chloride
Ex 3: Name Fe 2 O 3 Think reverse criss cross This iron must have a combining capacity of 3 So this is iron (III) oxide Ex 4: Name FeO This must be iron with a CC of 2 So this is iron (II) oxide
Flowchart for naming compounds
Check your understanding P. 191 q's 1-5 a-f only If finished, start vocab p. 196 choose 10
Naming molecular compounds What's it called?
How do we know how many of each? We use prefixes to show the number:
What would you call...
Rules for naming: Make sure both elements are non metals Similar to naming ionic compounds, only change the second element's name to -ide Don't use mono- for the first element, e.g. CO is carbon monoxide, not monocarbon monoxide
What would you call: CO₂ SO₃ N₂O₄ carbon dioxide sulfur trioxide dinitrogen tetraoxide
Check your understanding P. 195 q's 1-3 a-f only
Review p. 198-190 Also finish vocab p. 196 choose 10