Test Preparation

Test Preparation this is my second attempt at posting this puppy
Test Outline:
-16 multiple choice questions - you will be able to write on the multiple choice question sheet, mark it up, put "X's" through those letter choices that are obviously incorrect, hopefully there is only one answer left at that point (maybe two - one correct, one not - pick the correct answer)
-a 'bunch' of written/drawing/sketching/complete the table questions
-please know the difference between Lewis, energy level diagram, 3-D sketch, orbital sketch
-Total ~ 62 marks (or something right around there....)


SCH4U - Atomic Structure Unit Outline Once again.... things to know

Atomic models (Dalton, Thomson, Rutherford, Chadwick & Bohr)
sketch of the model and a brief description of each model; know which contains e,p & n and where they are located in the model

Photoelectric effect - describe it; impact of colour of light & intensity of light

Spectral lines bright and dark line spectrum of hydrogen -leading to the Bohr model
connecting the both line spectra to the Bohr model
Spectral line splitting
further refinements of the Bohr model
in terms of orbitals, what does each type of spectral line splitting identify?
-high resolution spectroscopy revealed...? influence of a magnet suggested...?

Energy level diagrams - know how to make them ...
fill according to the order of filling (spdf blocks on the periodic table)
-Aufbau, Hund's Rule & Pauli Exclusion

Electron configurations (complete, kernel, special cases (Cr column & Cu column), ions)
use the periodic table of elements as an aid [see Nelson page 188 for two helpful diagrams]
should be able to write the actual electron configuration for any element [includes the two columns of exceptions]
from electron configuration (either complete or kernel) identify the appropriate electron changes to achieve an ion charge

Quantum Numbers {n, l, m, s}
-connection of each number to spectroscopy evidence
-significance of each letter (n represents, l represents....)
-be able to interpret a set of numbers as being correct (possible orbital?) or incorrect (what is wrong with the number set?)

Quantum Model
-those orbitals - s and p [px py pz]
-never did sketch those d's....

Lewis Structure [following the rules] - draw a Lewis structure for any molecule
if you are going to follow the rules, then you had better know the rules, right? [Nelson text page 229]

Atomic Modeling
-based upon the Lewis structure - be able to sketch the 3D shapes, identify the name & bond angle
i.e. 4 atoms attached to central, no lone pairs = tetrahedral; 3 atoms attached, 1 lone pair = trigonal pyramidal
basic attributes of the various shapes [Nelson text pages 243-245]

Hybridization (sp3, sp2 and sp) - connection to molecular shapes (if you know the shape you know the type of hybridization)
-sp3 = tetrahedral or trigonal pyramidal or angluar (has four orbitals)
-sp2 = trigonal planar (has 3 orbitals)
-sp = linear (has 2 orbitals)
-be able to make the three different types of orbital sketchs (sp3, sp2 and/or sp)
-on orbital sketch be able to identify:
sigma (overlap with a hybrid) and pi bonds (p-orbital overlapping with another p-orbital)

Liquid state bonding (London, dipole-dipole, hydrogen bonding)
-from 3-D structure - be able to identify a molecule as polar/nonpolar
-if nonpolar - only LD
-if polar - LD and DD (maybe also HB if there is a H-N, H-O and/or H-F)

Solid state bonding [ionic, metallic, molecular & covalent network]
-know the properties of each type of solid [summary Nelson text page 273]
-ionic - metal + nonmetal - hard, generally: high melting point + soluble in water
-metallic - a metal (Fe(s), Pb(s)) - conductors, electron sea model (free moving 'sea' of valence electrons)
-molecular - nonmetal + nonmetal - CO2, H2O - generally low melting point, nonconductors
-covalent network - memorize the few of them (SiO2, SiC, CD) - very hard, high melting point, generally nonconductors

Laboratory Follow-Up

Ionic bonding - understand the relationship between: (1) melting point and ion size (2) melting point and charge difference [see previous post for a link]

Solubility:
-if it dissolves in water, it is polar, thus possesses LD & DD (maybe even HB)
-if it does not dissolve, it is nonpolar, thus possesses only LD (no DD/HB of any significance)

Consider the following links for some alcohol solubility information
http://www.solubilityofthings.com/water/alcohols/
This next one discusses solubility much further down the "page", though the initial information fits in nicely with the next organic functional group...
http://www.chemguide.co.uk/organicprops/alcohols/background.html

Question: Why do white bears dissolve in water? Answer: Because they are polar.

Paper

Can paper melt?

Solid State Bonding

Time to consider four solid state bonding forces. Solid state bonding forces are indicated by melting points.

(1) Molecular (CO2)

-weak between molecule forces





(2) Metallic (Fe(s), Pb(s))

-electron sea

http://www.chemguide.co.uk/atoms/bonding/metallic.html#top



(3) Ionic (NaCl(s))

-attraction of oppositely charged ions

-greater charge difference - greater attraction

-smaller ions, greater attraction

-greater attraction = higher melting point

http://www.saskschools.ca/curr_content/chem20/ionicpds/ionicex.html



(4)Covalent Network (SiO2, C(diamond))

-very strong force = highest melting point

-there are not really individual molecules

-each 'unit' is bonded to each surrounding 'unit'

http://www.chm.davidson.edu/vce/Crystals/NetworkSolids.html

http://www.chem.queensu.ca/people/faculty/mombourquette/FirstYrChem/Molecular/Solids/index.htm



The following link summarizes both liquid & solid state bonding forces. [Although it seems to exclude molecular solids - the weakest solid force.]

Liquid State Bonding

Three intermolecular forces to consider

• London Disperson Forces
• Dipole-dipole
• Hydrogen bonding

The strength of the bonding force is indicated by the boiling point of a substance.

Remember that boiling separates one molecule from another. Boiling DOES NOT break molecules apart - that is, DOES NOT separate atoms from each other.

A few useful links:

(1) London & dipole-Dipole

http://www.chemguide.co.uk/atoms/bonding/vdw.html#top

(2) H-bonding

http://www.chemguide.co.uk/atoms/bonding/hbond.html#top

(3) All 3 intermolecular forces

http://www.science.uwaterloo.ca/~cchieh/cact/c123/intermol.html

In order of increasing strength:

London (LDF) - weakest

• dependent upon the number of electrons
• greater number of electrons, greater London forces
• shape plays a role too, straight chain hydrocarbons tend to have higher bpt than branched chains of similar atom count

Dipole-Dipole (DDF)

• force of polar molecules
• polar molecules rely on shape of molecule
• polar molecules also have LD forces

H-bonding - strongest

• molecule must have H-N, H-O and/or H-F bond
• molecules will also have DDF and LDF

A typical liquid state bonding question would ask you to explain the difference in boiling points of various substances. Given a chemical formula, you need to be able to identify the type of liquid state bonding force involved with each molecule.

[The end of a much delayed post. Since water has all three bonding forces present, the chosen font colour for this little section is blue. Ready for a joke? Question: What did the sink say to the water faucet? Answer: You're a real drip. :<]