THS Chemistry with Ms. DiOrio - Home · Web viewUnit 3 Notes Guide – Part 2Name # Molecules Date:...
Transcript of THS Chemistry with Ms. DiOrio - Home · Web viewUnit 3 Notes Guide – Part 2Name # Molecules Date:...
Unit 3 Notes Guide – Part 2 Name # Molecules Date: ____________________ Block: Chemistry
I. Chemical Formulasa. Atoms vs. Molecules
i. Atoms are the ________________ unit of matter consisting of _______________
and a nucleus made up of _____________ and ________________.
ii. Molecules are groups of ___________ bonded together.
b. Elements vs. Compounds
i. An element consists of _______ type of atom defined by the number of
____________ in the nucleus.
An element can be found as an ______ or as a ______________
_____________
ii. A compound consists of ________ than one type of atom
A compound can ________ be found as a molecule
II. Molecular vs. Empirical Formulasa. Molecular Formula – the ________ chemical formula of a substance
b. Empirical Formula – the ________________ ratio of elements in the molecular formula
c. Molecular formula Empirical formula
i. Divide the subscripts by the ________________ ____________ ____________ (GCF)
ii.
Examples:
d. Empirical formula Molecular formula
i. You must be given the empirical formula and the molar mass of the molecular formula (also
called the molecular mass)
Formula Molar Mass GCF
MF Step 3 42.03 g/molStep 2
EF CH2 Step 1
1. Find the __________ ________ of the empirical formula
2. ____________ the molar mass of the MF by the molar mass of the EF to find the GCF1
CO2
Substance Molecular Formula Simplify the Ratio Empirical Formula
Sugar C6H12O6C 6
6
H 126
O66
C H2 O
Water H2O H 21
O 11
H 2O
3. _______________ the subscripts of the empirical formula by the GCF
III. Diatomic Moleculesa. Diatomic molecules are a special type of molecule consisting of ______ atoms of the _________
element bonded together (though they are still
considered an element!)
b. There are ______ diatomic molecules:
Br2 I2 N2 Cl2 H2 O2 F2
IV. Polyatomic Ionsa. A polyatomic ion is a _________________ chemical species
(ion) made up of ______ or ________ atoms bonded together.
b. Memorize these!
i. N ick the Camel ate Supper in Phoenix
Vowels = charge
Consonants = # oxygens
V. Metals vs. Nonmetalsa. There are three types of elements on the periodic table grouped by their chemical properties:
i. Metals
Metals are located on the _________ of the periodic table.
Properties of Metals:
a. Good ______________ of heat and electricity
b. High _________________ and
________________ points
c. High density
d. Hard
ii. Nonmetals
Nonmetals are located on the _________ of the
periodic table
Properties of Nonmetals:
a. Good _________________ (poor
conductors)
b. Brittle or gaseous
Practice #1: Identify the following as a metal or a nonmetal.
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Ammonium NH4+
Hydroxide OH-
Acetate C2H3O2-
Nitrite NO2-
Nitrate NO3-
Carbonate CO32-
Sulfite SO32-
Sulfate SO42-
Phosphate PO43-
Na C
F Zn
iii. Metalloids
Metalloids have properties of ______ metals and nonmetals.
They are located along the “________________” between
metals and nonmetals.
Some metalloids are ___________________________.
VI. Ionic Bondinga. Ionic Bonds form when electrons are _____________________ between two atoms
b. Electronegativity is a chemical property that describes an element’s ability to ________ electrons.
i. Nonmetals have ________ electronegativity (they tend to gain electrons)
ii. Metals have ______ electronegativity (they tend to lose electrons)
c. Ionic bonds form from the interaction of ions
i. How do charges interact?
______ charges repel but opposite charges ____________.
d. Ionic bonds can only form between a ___________ and an _________
i. An element forms a cation when it _________ electrons, so we need an element with
_________ electronegativity
___________ easily lost electrons, so they are the most likely source of __________
ii. To gain an electron, an element must have a _________ electronegativity. Therefore,
_________________ are the most likely source of ____________.
Ionic Bond = cation + anion
Ionic Bond = ______________ + ____________________e. Drawing Ionic Bonds
i. We can use Lewis dot diagrams or Bohr models to
represent ionic bonds
ii. The arrow indicates where the ___________ is
transferred _____
iii. It can also represent _____________ atoms donating
______________ electrons.
Practice #2: Draw the ionic bonds formed for each as a Lewis Dot diagram with arrows.KBr K Br CaCl2
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Cl Ca Cl
VII. Ionic Nomenclaturea. A binary compound is a compound containing only ______ elements.
b. Ionic compounds are named so that the ____________ ion (_________) comes first and the
_______________ ion (______________) comes last ending in -______.
Metal + Nonmetal-ideExamples
NaCl Sodium chloride
CaBr2 Calcium bromide
K3P Potassium phosphide
LiO Lithium Oxide
Ag2S Silver sulfide
c. Naming with Transition Metals
i. Main group elements always form the same ion with the same __________.
ii. Transition metals can form ions with _______________ different charges.
iii. You determine the charge on a transition metal using algebra. Remember, the charges have to
add up to 0 for the compound to be neutral!
(# metal atoms)(charge of metal) + (# anions)(charge of anion) = 0Examples
CuO1x + 1(-2) = 0
x – 2 = 0x = +2
Fe3P2
3x + 2(-3) = 03x – 6 = 0
x = +2
PbO2
1x + 2(-2) = 0x – 4 = 0x = +4
Cu2SO4
2x + 1(-2) = 02x – 2 = 0
x = +1
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Practice #3
KCl
CaO
K2S
NaF
BaBr2
Practice #4
NiBr
Cu2S
PbSO4
iv. When naming compounds with transition metals, we have to indicate the charge by using roman
numerals (I, II, III, IV, V, VI, VII, etc.)
Transition metal (Roman #) + Nonmetal-ideExamples
CuO Copper (II) oxide
PbO2 Lead (IV) oxide
Fe3P2 Iron (II) phosphide
v. There are _______ exceptions to the roman numeral rule:
Cadmium (______)
Zinc (______)
Silver (______)
a. Naming with Polyatomic Ions
vi. The name of the polyatomic is used
________________ any changes to the ending
vii. Remember, the _______________ ion always comes
first!
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Practice #5
Cu2S
NiBr
FeCl3
Examples
NaOH Sodium hydroxide
CaCO3 Calcium carbonate
NH4OH Ammonium hydroxide
Practice #6
CaSO4
K3PO4
NH4Cl
b. Summary: Steps to naming ionic compounds
1. Write the name of the positive ion (metal or polyatomic)
2. Include a roman numeral in parentheses for transition metals to indicate charge
3. Write the name of the negative ion (nonmetal or polyatomic)
Change nonmetal names to end in -ide
VIII. Writing Ionic Formulasa. Steps to writing ionic formulas:
1. Write the cation and anion with their ___________ as superscripts
2. _________ & __________ the absolute value of the charges to become the subscript on the
opposite ion
3. If necessary, _____________ the subscripts by dividing by the greatest common factor
*Polyatomic ions should be put in parentheses if there are multiple*
Examples
Sodium chloride Na+ Cl- Na1Cl1 NaCl
Calcium phosphide Ca2+ P3- Ca3P2 Ca3P2
Magnesium oxide Mg2+ O2- Mg2O2 MgO
Silver sulfide Ag+ S2- Ag2S Ag2S
Magnesium hydroxide Mg2+ OH- Mg1(OH)2 Mg(OH)2
Lead (I) oxide Pb+ O2- Pb2O1 Pb2O
Magnesium sulfate Mg2+ SO42- Mg2(SO4)2 MgSO4
Practice #7
Lithium bromide
Calcium sulfide
Ammonium chloride
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Na2OO2-Na+
Magnesium carbonate
Cobalt (III) sulfide
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