Transcript Ionic Bonding & Naming

Ionic Bonding
Naming and formula
writing
Mrs. Kay & Ms. Cleary
Chemistry 11
Read pages 158-168
Recall
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Sodium has 1 valence
electron
Atoms of different
elements have different
numbers of electrons
Each shell is filled up
before electrons move to
the next shell found
further away from the
nucleus
Ex: Sodium has 2 e- on
the 1st energy level, 8 e- on
the 2nd energy level, and 1
e- on the 3rd energy level.
Valence electrons
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Period number indicates the number of
electron shells
Group number indicates the number of valence
electrons (look at the second digit of the group
number)
Trends:
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Elements of the same
group have similar
chemical properties
because they have the
same number of
electrons in their outer
shell or valence shell
Group 1 metals reacting
with water
Reasons for reactions
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Group 18, the noble gases are the most stable of
elements because their valence shell is full with
electrons
Less energy required to support the atom
Other atoms react in attempt to achieve nobel
gas configuration, same number of valence
electrons as a noble gas.
Lewis Dot structures
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Visual representation of an element and only its
valence electrons
sodium, Na has 1 valence so it has 1 dot representing
that electron. (group 1)
Chlorine, Cl has 7 electrons. (group 17)
Electrons get placed up along 4 sides of the element
before they double up!
Ionic Bonding
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attraction between oppositely charged ions formed when metallic
ions (+) transfer electron(s) to nonmetallic ions (-)
Difference of electronegativity greater than 1.7
Ex: NaCl
Not always 1:1 ratio, sometimes need to use
subscript to show the number of atoms
Ex: CaCl2 The 2 is a subscript, it shows that 2
atoms of chlorine bond with one atom of
calcium.
Zero Sum Rule: the charges need to add up to
zero
Naming Ionic
Compounds
Simple or Binary Ionic
Compounds (Formula to Name)
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KBr
Name the (cation) metal first
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Name the root of the (anion) non-metal, change
the (suffix) end to –ide
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Potassium
Bromine becomes bromide
Put together: Potassium bromide
Practice
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Na2O
Name the metal:
Name the non-metal:
Sodium
Oxide
Put them together to get: Sodium Oxide.
• It takes two Na+ to combine with one O2- to
observe the Zero Sum Rule!
Simple or Binary Ionic
Compounds (Name to Formula)
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To write the formula from a name first you must
look at the charges.
Remember ionic compounds are made up of
cations and anions (oppositly charged ions) but
together the compound has no charge- the
charges balance each other out.
“Cross-over Method”
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This is a method used to make sure your
compound is balanced.
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Write the formulas of the ions beside each other,
then cross the number of the charge of the cation so
that it becomes the subscript of the anion. Then
cross over the number of the charge on the anion so
that it becomes the subscript of the cation.
Mg2+
Cl1MgCl2
Simple or Binary Ionic
Compounds (Name to Formula)
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If you’re given the name, can you write the
formula?
Strontium nitride
 Strontium is Sr2+
 Nitride is N3 We must combine them to be equal to zero
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Need 3 Sr2+ to combine with 2 N3-
Answer is Sr3N2
Multivalent Ionic bonding
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Whenever the periodic table of ions has a split
cell, we must choose or indicate which charge
we are referring to in the chemical equation.
Look at Iron, the charge on Fe is written as a roman
numeral between the cation and the anion.
 There is an option of Fe2+ and Fe3+
 FeO would be called Iron (II) oxide
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It takes Fe2+ to balance out charges with O2 We indicate the optional charge with roman numerals; 2=
II, 3=III, 4=IV and so on
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Practice naming
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2.
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4.
FeCl2
MnO
Fe2O3
TiO2
1. Iron (II) chloride
2. Manganese (II) oxide
3. Iron (III) oxide
4. Titanium (IV) oxide
Polyatomic ions
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Ions that are made of multiple atoms covalently
bonded together.
We treat them like a unit or package
When we need more than one, must be put in
brackets!!
Example: sulphate, SO42-
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Aluminum sulphate = Al2(SO4)3
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Because is Al3+ and SO42- must combine to Zero
Practice
1.
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3.
4.
5.
NaOH
K3PO4
CsMnO4
Ca(HCO3)2
Cu(NO3)2
1. Sodium hydroxide
2. Potassium phosphate
3. Cesium permanganate
4. Calcium hydrogen carbonate
5. Copper (II) nitrate
Homework:
1.
2.
Don’t forget to read over the textbook pages
for furhter understanding
Work on handouts to continue practice with
naming and proper formula writing (IUPAC =
international naming method, what we
learned)
Test what you know here:
http://science.widener.e
du/svb/tutorial/namingc
sn7.html