Inside an Atom
ñ The number of protons is the same as the atomic number of the element.
ñ The number of neutrons is the atomic mass minus the atomic number.
ñ The number of electrons is the same as the number of protons, for a neutral atom.
ñ More electrons than protons? Then it's a NEGATIVE ion.
ñ Fewer electrons than protons? Then it's a POSITIVE ion.
Fill in the following table.
Element Symbol (include charge) / Number of Protons / Number of Neutrons / Number of ElectronsAl3+
S2-
23 / 22
35 / 28
8 / 10
Re7+
U6+
Ge4-
82 / 78
53 / 54
Bohr-Rutherford Diagrams
ñ In the centre, write the number of protons and neutrons
ñ Up to 2 electrons in the first shell
ñ Up to 8 electrons in each of the next shells
ñ Fill a shell with 8 electrons before going on to the next one
Examples:
Draw Bohr-Rutherford Diagrams for each of the following elements:
a) Lithium b) Argon c) Phosphorous
d) Be e) O2- f) Mg2+
Name → Formula
ñ Look up each ion on the list or the periodic table
ñ A roman numeral tells you the charge on a metal ion
ñ Criss-cross the charges and simplify as necessary
ñ “Packages” / “Polyatomic ions” go in parentheses ( ) if there are more than one
Examples:
sodium iodide Na+ I- NaI
lithium carbonate Li+ CO32- Li2CO3
calcium hydroxide Ca2+ OH- Ca(OH)2
ammonium phosphate NH4+ PO43- (NH4)3PO4
Create the chemical formula for each of the following:
a) potassium chlorideb) potassium oxide
c) magnesium nitrate
d) aluminum chloride
e) calcium oxide / f) zinc carbonate
g) vanadium(V) nitrate
h) chromium(VI) carbonate
i) lead(IV) phosphate
j) gallium(I) sulfate
Formula → Name
ñ Look up each ion on the list or the periodic table
ñ If the second element is from the periodic table, you must change its ending to “ide”
ñ Determine the charge on the atom if it can have more than one. Show this with a roman numeral.
Examples:
NaI Na+ I- sodium iodide
Li2CO3 Li+ CO32- lithium carbonate
Ca(OH)2 Ca2+ OH- calcium hydroxide
CuSO4 Cu2+ SO42- copper (II) sulfate
Create the chemical name for each of the following:
a) KClb) K2O
c) Mg(NO3)2
d) AlCl3
e) CaO
f) ZnCO3 / g) ScN
h) NiF2
i) NiF3
j) MnO2
k) Sn3(PO4)4
Name → Formula
ñ Use the periodic table to determine which elements are in your compound
ñ Use the prefixes to determine how many of each element are present
Examples:
nitrogen dioxide one nitrogen, two oxygen NO2
nitrogen monoxide one nitrogen, one oxygen NO
dinitrogen pentaoxide two nitrogen, five oxygen N2O5
dichlorine heptaoxide two chlorine, seven oxygen Cl2O7
Create the chemical formula for each of the following:
a) phosphorous trichlorideb) arsenic pentabromide
c) iodine trichloride
d) carbon monoxide
e) diphosphorous pentoxide / f) boron trifluoride
g) dichlorine heptoxide
h) diphosphorous monosulfide
i) carbon tetrachloride
j) nitrogen trihydride
Formula → Name
ñ Determine the elements present. Change the ending of the second one to “ide”.
ñ Put a prefix in front of each one, to show how many atoms there are of it.
◦ The only trick is that if there is only one of the first element, we do not write “mono” as these rules state. We just don't write anything.
Examples:
P2S two phosphorous, one sulfur diphosphorous monosulfide
ICl3 one iodine, three chlorine iodine trichloride (not monoiodine trichloride)
SbF5 one antimony, five fluorine antimony pentafluoride
Create the chemical name for each of the following:
a) P4O10b) SeCl2
c) NO
d) N2O
e) NO2 / f) SF8
g) BCl3
h) As2O5
i) P4S5
j) SbF3
To balance a chemical equation you need to make sure each side of the equation has the same number of each type of atom. The easiest way to balance these equations is to go from left to right and balance each atom as you come across it.
a) S + O2 → SO2
b) HCl + Na2SO3 → NaCl + H2O + SO2
c) H2O2 → O2 + H2O
d) As4S6 + O2 → As4O6 + SO2
e) Sc2O3 + H2O → Sc(OH)3
f) C2H5OH + O2 → CO2 + H2O
Synthesis reactions occur when two or more reactants combine to form a product.
You can make ionic compounds out of their constituent elements. Want to make NaCl? You can combine Na with Cl2:
2 Na + Cl2 → 2 NaCl
Predict the products of the following synthesis reactions
a) Ca + O2 → b) K + F2 →
c) Zr + I2 → d) Sc + Br2 →
e) Fe + O2 f) Cu + Cl2 →
Decomposition reactions occur when a reactant breaks apart to form two or more products.
Examples:
Electrolysis of water: 2 H2O(l) → 2 H2(g) + O2(g)
Explosion of sodium azide: 2 NaN3(s) → 3 N2(g) + 2 Na(s)
Decomposition of Simple Compounds
You can break up most ionic and covalent compounds into their constituent elements – all it requires is energy. Want to get Na and Cl2 from a sample of salt (NaCl)? Heat it to 2000ºC and pass an electric current through it:
2 NaCl → 2 Na + Cl2
Enough heat and electric current can break any compound into its constituent elements.
Remember HOFBrINCl !
Predict the products of the following decomposition reactions.
a) Al2O3 → d) ICl7 →
b) Fe3N2 → e) ScF3 →
c) H2O → f) H2NO3 →
Complete vs Incomplete Combustion
If there's enough oxygen (O2) around, then the carbon and hydrogen will get fully oxidized:
CH4 + O2 → CO2 + H2O
C4H8O2 + O2 → CO2 + H2O
If there isn't enough oxygen (O2) around, then the carbon and hydrogen will not get fully oxidized:
CxHyOz + O2 → CO2 + H2O + CO + soot
Incomplete combustion produces smoke and carbon monoxide.
Assume that there is enough O2 around. Write balanced chemical equations for the combustion of
a) C3H8
b) C21H30O2
c) C20H12
d) C9H13
e) C3H8
Single Displacement Reactions happen when one element replaces another in a compound.
Metal higher on the list = able to replace elements lower than themselves on the list in compounds.
You will be asked to predict what the products of particular reactions are.
ñ If no reaction will occur, we write “NR”.
Predict the products of these reactions (no need to balance):
a) Mg + CuF2 →
b) K + CoBr3 →
c) Ag + NaCl →
d) Ca + Sn(NO3)2 →
e) Sn + Ca(NO3)2 →
f) NaI + Cl2 →
g) CuBr + F2 →
h) CaCl2 + F2 →
i) KBr + Cl2 →
To predict the products of single displacement reactions:
1. Identify the ions that are present in each of the original compounds.
2. Switch! Put the “–“ ion from one compound with the “+” ion from the other compound.
3. Look up each of the new compounds in the chart provided.
ñ If they're both “aq” in the chart, then you've formed soluble compounds and no reaction has occurred.
ñ If one is “s” in the chart, then that compound is not soluble – it's a precipitate (a solid that “falls out” of the solution) and a reaction has occurred!
Questions
Predict the products of the following reactions:
1. NaOH(aq) + CaBr2(aq) →
2. Pb(NO3)2(aq) + HCl(aq) →
3. Na2CO3(aq) + KF(aq) →
4. AgNO3(aq) + CuSO4 →
5. AgF(aq) + NiCl2(aq) →
One important type of double-displacement reaction is the reaction between an acid and base:
HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq)
Acids have an H+ ion, and some bases have an OH- ion. When these two ions come together, they form liquid water. Eventually, the solution may not be acidic or basic – it may be neutral. Thus, this type of reaction is called a neutralization reaction.
To Identify the type of chemical reaction involved:
Follow this series of questions. When you can answer "yes" to a question, then stop!
1. Does your reaction have oxygen as one of it's reactants? If yes, then it's a combustion reaction.
ñ The products will be the oxides of the atoms being combusted
2. Does your reaction have two elements combining? If yes, then it's a synthesis reaction
ñ Determine the simple ionic compound that is formed when they combine
3. Does your reaction have only one molecule on the left? If yes, then it's a decomposition reaction
ñ Figure out how it decomposes. Remember: Carbonates create carbon dioxide
4. Is your reaction between one element and one compound? If yes, then it's single displacement
ñ You'll have to determine if a reaction occurs, using the activity series
5. Is your reaction between two compounds? If yes, then it's double displacement
ñ You'll have to determine if a reaction occurs, using the solubility table
Questions
1. Indicate the type of reaction taking place. Predict the products. Balance the equation.
a) ____ NaBr + ____ H3PO4 →
b) ____ Ca(OH)2 + ____ Al2(SO4)3 →
c) ____ Mg + ____ Fe2O3 →
d) ____ C2H4 + ____ O2 →
e) ____ PbSO4 →
f) ____ NH3 + ____ I2 →
g) ____ H2O + ____ SO3 →
h) ____ H2SO4 + ____ NH4OH →
Predict whether a solution would be acidic, basic or neutral after adding each of the following:
a) HCl
b) H2SO4
c) Mg(OH)2
d) Sc(OH)3
e) HOH
Compare Acids and Bases by filling in this chart:
Acids / BasesH+ concentration (High or low?)
OH- concentration (High or low?)
Taste
Turns litmus paper what color?
pH (less or more than 7?)
Name each of the following acids:
a) HF
b) HCl
c) HBr
d) HI
e) HNO3
f) H2SO4
g) H2CO3
h) H3PO4
Name two ways to measure the pH of a solution.