Class Notes

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material
Science 10 Review
A. The Atom
 proton  p+  positive charge
 neutron  n0 
zero charge
 electron e–  negative charge
 electrons are found in a cloud region around
the nucleus
 nucleus contains the protons and neutrons
which make up most of mass of atom
 mass number = # protons + # neutrons
# neutrons = mass number - # protons
 isotope = atoms with the same # of protons
but a different # of neutrons
(different mass numbers)
eg) carbon-12  6 p+, 6 n0
carbon-14  6 p+, 8 n0
B. Periodic Table
arranged in groups (columns) and
periods (rows)
group number = number of outer level
(valence) eperiod number = number of energy levels
occupied by eEx. Na
Group number = 1
Period number = 3
This info is helpful for drawing Energy Level
Diagrams
C. Energy Level Diagrams
atoms are electrically neutral
that the # of p+ = # of e-
which means
maximum number of e-: 3rd level = 8 e2nd level = 8 e1st level = 2 e-
Examples
1 e8 e2 e-
1 e2 e-
11 p+
3 p+
Na
Li
D. Ions
ions are particles or groups of particles that
have a net charge (either positive or
negative)
neutral atoms are unstable if their valence level
is not full
atoms will strive to satisfy the octet rule in order
to become stable…in other words, they strive to have
a full valence level and do so by giving away
or taking e-
metals  give away e- and become positive
ions
eg) Na+, Ca2+, Fe3+
non-metals take e- and become negative
ions
eg) Cl-, P3-, O2-
Examples
1 e8 e2 e11
p+
Na
sodium atom
8 e2 e11 p+
Na+
sodium ion
7 e8 e2 e17
p+
Cl
chlorine atom
8 e8 e2 e17 p+
Cl–
chloride ion
Your Assignment: pgs 1-3 in workbook
E. Elements
metals exist as single atoms
eg) Li(s), Cu(s), Hg(l)
nonmetals and hydrogen do not exist as single
atoms – MUST MEORIZE!
H2
N2
O2
F2
P4
S8 Cl2
Br2
I2
Try These:
1. Cu(s) = copper
2. O2(g) = oxygen gas
3. Al(s) = aluminum
4. fluorine gas = F2(g)
5. barium = Ba(s)
6. nitrogen gas = N2(g)
F. Ionic Compounds
 metals + nonmetals or polyatomic ions
 monovalent eg) K+, Be2+ or multivalent metals
eg) Fe3+, Fe2+
charges on the ions are the result of taking or
giving eto go from formula to name: name of first ion,
then brackets for charge if multivalent,
then name for second ion
i.e. first element ( ) second element-ide
eg) AlCl3 = aluminum chloride
Fe2O3 = iron (III) oxide
Try These:
1. Zn3P2 = zinc phosphide
2. NaNO3 = sodium nitrate
3. NiF3 = nickel (III) fluoride
4. MnO2 = manganese (IV) oxide
5. Cr2(SO4)3 = chromium (III) sulphate
to go from name to formula: write the symbol
for each ion, then add subscripts to balance
charges
eg) calcium sulphide = CaS
iron (II) hydroxide = Fe(OH)2
Try These:
1. lithium bromide = LiBr
2. sodium phosphate = Na3PO4
3. magnesium nitride = Mg3N2
4. ammonium sulphate = (NH4)2SO4
5. calcium phosphate =
Ca3(PO4)2
Hydrated Compounds
 ionic compounds containing water in their
structure
water is represented by “xH2O” in the formula
where x is the number of water molecules
prefixes:
1 = mono
6 = hexa
2 = di
7 = hepta
3 = tri
8 = octa
4 = tetra
9 = nona
5 = penta
10 = deca
to go from name to formula: give the ionic name
for the first part of the compound, then name the
“xH2O” part as prefix + “hydrate”
eg) NaF3H2O = sodium fluoride trihydrate
CuSO45H2O = copper (II) sulphate pentahydrate
to go from name to formula: first part is the
same as before …look up the symbol for each
ion then balance the charges using subscripts,
then for the hydrate part…add “xH2O” where
x is the number given in the prefix
eg) iron (III) nitrate nonahydrate = Fe(NO3)39H2O
sodium chlorate tetrahydrate = NaClO34H2O
nickel (II) sulphite heptahydrate = NiSO37H2O
Your Assignment: pgs 3,4 in workbook
G. Molecular Compounds
 nonmetals only
 e- are shared therefore no ions are formed
 no charges involved
 use prefixes in naming
to go from formula to name: name of first
element (including prefix if necessary),
then name for second element with “ide”
ending (including prefix)
i.e. ___first element ___second element -ide
eg)
N2O = dinitrogen monoxide
CO2 = carbon dioxide
P4O10 = tetraphosphorus decaoxide
to go from name to formula: write the symbol
for each element, then use the prefixes to
determine the subscripts
eg)
carbon monoxide = CO
carbon tetrachloride = CCl4
remember the please memorize:
NH3(g)= ammonia
H2O(l) = water
H2S(g) = hydrogen sulphide
HF, HCl, HBr, HI = no prefixes
CH4(g)= methane
CH3OH(l) = methanol
C2H6(g)= ethane
C2H5OH(l) = ethanol
C6H12O6(s)= glucose
C12H22O11(s)= sucrose
O3(g)= ozone
H2O2(l)= hydrogen peroxide
H. Acids
 always have aqueous (aq) as the state and
always have hydrogen
Rules
1. hydrogen____ide
2. hydrogen ____ate
3. hydrogen ____ite
becomes hydro___ic acid
becomes _______ic acid
becomes ______ous acid
Try These:
1. hydrogen iodide =hydroiodic acid HI(aq)
2. hydrogen phosphate = phosphoric acid H3PO4(aq)
3. hydrogen nitrite = nitrous acid
HNO2(aq)
4. hydrogen sulphite = sulphurous acid
H2SO3(aq)
Your Assignment: pgs 5-7 in workbook
I. States
acids – always (aq)
elements – can be (s), (l) or (g)…see
periodic table
molecular compounds – can be (s), (l), or (g)
ionic compounds - If not in a solution always (s)
- If in a solution either (s) or
(aq)…look up on the solubility
chart
Try These:
1. NaCH3COO(aq )
6. CaCO3( s )
2. BaSO4( s )
7. FeSO4( aq)
3. KOH( aq)
8. (NH4)2S( aq )
4. Pb(NO3)4( aq )
9. Pb(SO4)2( aq )
5. Hg(CH3COO)2(aq )
10. Ca3(PO4)2( s )
J. Chemical Reactions
 endothermic
vs. exothermic
reaction types:
1. hydrocarbon combustion
C?H? + O2(g)  CO2(g)
eg) CH4(g) + 2 O2(g)
2. simple composition
element + element
eg) 2 Mg(s)
+
+
 CO2(g)
H2O(g)
+
2 H2O(g)
 compound
O2(g)
 2 MgO(s)
3. simple decomposition
compound  element + element
eg) 2 H2O(l)  2 H2(g) + O2(g)
4. single replacement
element + compound
 element + compound
eg) Cu(s) + 2 AgNO3(aq)  2 Ag(s) + Cu(NO3)2(aq)
5. double replacement
compound + compound
 compound + compound
eg) Pb(NO3)2(aq) + 2 KI(aq)  2 KNO3(aq) + PbI2(s)
Balancing Reactions
law of conservation of matter says that matter
cannot be created or destroyed, it can only
change forms
we must balance
matter
CH4 (g) +2O2(g) 
chemical equations to conserve
CO2(g) + 2H2O(g)
2 C2H6 (g) + 7 O2(g)  4 CO2(g) + 6 H2O(g)
Your Assignment: pg 8, 1st half p. 9
Predicting Reactions
Try the following:
Potassium iodide solution is added to
lead (II) nitrate solution.
2 KI(aq) + Pb(NO3)2(aq)  2 KNO3(aq) + PbI2(s)
NOTE:
-SR and DR reactions always happen in solutions so for
ionic compounds check solubility table
-Composition and decomposition do NOT happen in
solutions so ionic compounds are (s)
Predicting: single replacement
Copper metal is added to a solution of silver nitrate
Cu(s) + 2 AgNO3(aq)  2 Ag(s) + Cu(NO3)2(aq)
Chlorine gas is bubbled through a solution of sodium
phosphide
6 Cl2(g) + 4 Na3P(aq)  P4(s) + 12 NaCl(aq)
Your Assignment:
pg 2nd half p. 9
K. Significant Digits
any digit from 1-9 is significant
trailing zeros are significant eg) 6.3800,
12 000
 “sandwich” zeros are significant eg) 2.04,
1005.002
 leading zeros are not significant eg) 0.0065
 counted objects and constants are not included
in sig digs
/ : multiply or divide then round answer
to the lowest number of sig digs
+/ : add or subtract then round answer to
the lowest number of decimal places
L. The Mole
it is a number= 6.02 x 1023 “items”
1. Molar Mass
sum of the individual atomic masses for
each element in a compound
eg)
CO2 = 44.01 g/mol
Al(OH)3 = 78.01 g/mol
Cu(ClO3)2 = 230.45 g/mol
2. Mole/Mass Calculations
n= m
M
where:
m = nM
n = number of moles in mol
m = mass in g
M = molar mass in g/mol
Example 1
How many moles are in 8.06 g of magnesium
oxide?
m = 8.06 g
M = 40.31 g/mol
n=?
n = m
M
=
8.06 g
40.31 g/mol
= 0.1999503 mol
= 0.200 mol
Example 2
What is the mass of 0.677 mol of potassium
sulphide?
n = 0.677 mol
M = 110.27 g/mol
m=?
m = nM
= (0.677 mol)(110.27 g/mol)
= 74.65…g
= 74.7 g
Your Assignment: p. 10 & 1st half p. 11
Your Review Assignment: finish p. 11 – p. 13
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