Transcript Chemical Nomenclature Ionic Compounds BaCl barium chloride

Chemical Nomenclature
• Ionic Compounds
– often a metal + nonmetal
– anion (nonmetal), add “ide” to element name
BaCl2
barium chloride
Known as a subscript
K2O
Mg(OH)2
KNO3
potassium oxide
magnesium hydroxide
potassium nitrate
An ion is an atom, or group of atoms, that has a net
positive or negative charge.
cation – ion with a positive charge
If a neutral atom loses one or more electrons
it becomes a cation.
Na
11 protons
11 electrons
Na+
11 protons
10 electrons
anion – ion with a negative charge
If a neutral atom gains one or more electrons
it becomes an anion.
Cl
17 protons
17 electrons
Cl-
17 protons
18 electrons
Forming Cations & Anions
A CATION forms
when an atom
loses one or
more electrons.
Mg -->
Mg2+
+ 2 e-
An ANION forms
when an atom
gains one or
more electrons
F + e- --> F-
Do You Understand Ions?
How many protons and electrons are in
27 3+
13 Al
?
13 protons, 10 (13 – 3) electrons
How many protons and electrons are in
78 234 Se
34 protons, 36 (34 + 2) electrons
?
A monatomic ion contains only one atom
Na+, Cl-, Ca2+, O2-, Al3+, N3-
A polyatomic ion contains more than one atom
OH-, CN-, NH4+, NO3-
Compound Names and Formulas
A.
Naming ionic compounds
1.
Ionic - transfer of electrons - causing one
element to become a positive ion (cation) and
one element to become a negative ion (anion)
2.
the positive ion always come first
NaCl is never written as ClNa
3.
The name is derived from the ions that make it up
a.
naming binary ionic compounds - two
elements
i.
ii.
the positive ion is simply the name ion
the element
Na+ is sodium
Ba++ is Barium
b.
the negative ion’s ending is changed to ide
i.
c.
chlorine - Cl is changed to Cl- - chloride
some polyatomic ions are name according to
their oxygen content
Sulfate and sulfite
SO4-- and SO3--
d.
Some cations must show their charge
Fe++ is known as the Iron II ion
Fe+++is known as the Iron III ion
e.
when writing chemical formulas from their names
- the number of positive ions must equal the number
of negative ions
Sodium fluoride
Na+F - - these charges are balanced
Calcium chloride
Ca++Cl- - these charges are not balanced so we must adjust the
subscripts so the number of + equals the number of Ca++Cl2Remember - Charges must be balanced - so you must
have 2 -1’s to balance the +2
Coefficient
2NH4+
Ammonium
subscript
+
CO3-2 ==>
carbonate
(NH4+ ) 2 CO3-2
Ammonium carbonate
Use coefficients to balance the total number of atoms Always balance charges first using subscripts
+1 with -1
Ammonium with acetate
NH4+
Ammonium
+
C2H3O2acetate
==> NH4+ C2H3O2Ammonium Acetate
Cu+1 + C2H3O2- => Cu+1C2H3O2copper (I)
acetate
copper (I) acetate
+1 with -2
2 NH4+
Ammonium
+
There is an issue
CO3 -Carbonate
( NH4+ ) CO -3
2
Ammonium carbonate
You must make the charges equal
now you must balance it according to the conservation of
mass
+1 with -3
You must always have the charges equal
- so must have 3 +1 with the -3
3NH4+
+
PO4 -3
==> (NH4+)3PO4-3
Ammonium
phosphate
Ammonium phosphate
+2 with -1
You must always have the charges equal
- so must have 2 -1’s to equal the +2
Ca+2 +
Calcium
2C2H3O2 -1 ===> Ca+2(C2H3O2-)2
acetate
Calcium acetate
+2 with -2
Since the charges are equal - you simply put them together
Ca + 2 +
Calcium
CO3 -2
===> CaCO3
Carbonate
Calcium Carbonate
+2 with -3
Since the charges are not equal - you must find the
LCD for 2 and 3 which is 6 so
3Ca + 2
Calcium
+ 2 PO4
-3
==> Ca+23(PO4 -3 )2
Phosphate
Calcium Phosphate
+3 with -1
Al+3
Aluminum
+ 3 C2H3O2-  Al+3(C2H3O2-)3
Acetate
Aluminum Acetate
+3 with -2
2Al+3 +
Aluminum
3CO3 --
 Al+32 (CO3 --)3
Carbonate
Aluminum Carbonate
+3 with -3
Al +++
Aluminum
+
PO4 --Phosphate

Al+++PO4 --Aluminum Phosphate
A molecular formula shows the exact number of
atoms of each element in the smallest unit of a
substance
An empirical formula shows the simplest
whole-number ratio of the atoms in a substance
molecular
empirical
H2O
H2O
C6H12O6
CH2O
O3
O
N2H4
NH2
• Molecular compounds
• nonmetals or nonmetals + metalloids
• common names
• H2O, NH3, CH4, C60
• element further left in periodic table
is 1st
• element closest to bottom of group is
1st
• if more than one compound can be
formed from the same elements, use
prefixes to indicate number of each
kind of atom
• last element ends in ide
Molecular Compounds
HI
hydrogen iodide
NF3
nitrogen trifluoride
SO2
sulfur dioxide
N2Cl4
dinitrogen tetrachloride
NO2
nitrogen dioxide
N2O
dinitrogen monoxide
TOXIC!
Laughing Gas
Mixed Practice
•
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•
•
•
•
Dinitrogen monoxide
Potassium sulfide
Copper (II) nitrate
Dichlorine heptoxide
Chromium (III) sulfate
Iron(III) sulfite
Calcium oxide
Barium carbonate
Iodine monochloride
1.
2.
3.
4.
5.
6.
7.
8.
9.
N2O
K2S
Cu(NO3)2
Cl2O7
Cr2(SO4)3
Fe2(SO3)3
CaO
BaCO3
ICl
Mixed Practice
•
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•
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•
BaI2
P4S3
Ca(OH)2
FeCO3
Na2Cr2O7
I2O5
Cu(ClO4)2
CS2
B2Cl4
1.
2.
3.
4.
5.
6.
7.
8.
9.
Barium iodide
Tetraphosphorus trisulfide
Calcium hydroxide
Iron (II) carbonate
Sodium dichromate
Diiodine pentoxide
Cupric perchlorate
Carbon disulfide
Diboron tetrachloride
Examples of Older Names of Cations
formed from Transition Metals
(memorize these!!)
From Zumdahl
An acid can be defined as a substance that yields
hydrogen ions (H+) when dissolved in water.
HCl
•Pure substance, hydrogen chloride
•Dissolved in water (H+ Cl-), hydrochloric acid
An oxoacid is an acid that contains hydrogen,
oxygen, and another element.
HNO3
nitric acid
H2CO3
carbonic acid
H2SO4
sulfuric acid
HNO3
• Transition metal ionic compounds
– indicate charge on metal with Roman numerals
FeCl2
2 Cl- -2 so Fe is +2
iron(II) chloride
FeCl3
3 Cl- -3 so Fe is +3
iron(III) chloride
Cr2S3
3 S-2 -6 so Cr is +3 (6/2) chromium(III) sulfide
Oxidation and reduction
1.
Oxidation and reduction (redox reactions)
A.
Oxidation - loss of electrons
B.
Reduction - gain of electrons
Oxidation-reduction reactions MUST
happen at the same time
C.
Oxidation numbers - number of electrons
gained, lost or shared
1.
how to assign oxidation numbers
a.
free elements are assigned an
oxidation number of zero
i.
free element - any un- combined
element - this includes the 7 diatomics
H2, N2, O2, F2, Cl2, Br2, I2
These 7 elements must be together if they are alone
b.
mono atomic ion's charge equals their
oxidation number
i.
Na+1= +1
ii.
S-2 = -2
c.
hydrogen's oxidation is =1
d.
oxygen's oxidation number is -2
except in peroxides. In peroxides,
the oxidation is -1
e.
the sum of the oxidation numbers of a
compound must add up to be zero
f.
the sum of the oxidation numbers of a
polyatomic ion must add up to equal
its charge
4. The oxidation number of hydrogen is +1
except when it is bonded to metals in
binary compounds. In these cases, its
oxidation number is –1.
5. Group IA metals are +1, IIA metals are +2
and fluorine is always –1.
6. The sum of the oxidation numbers of all
the atoms in a molecule or ion is equal
to the charge on the molecule or ion.
Oxidation numbers of all the
elements in HCO3- ?
+1
-2
HCO3+1 ?+4 -6
H = +1
O = -2
C = +4
= -1
Oxidation number
The charge the atom would have in a molecule (or an
ionic compound) if electrons were completely transferred.
1. Free elements (uncombined state) have an oxidation
number of zero.
Na, Be, K, Pb, H2, O2, P4 = 0
2. In monatomic ions, the oxidation number is equal to
the charge on the ion.
Li+, Li = +1; Fe3+, Fe = +3; O2-, O = -2
3. The oxidation number of oxygen is usually –2. In H2O2
and O22- it is –1.
Try some
find the oxidation numbers for each element
Formula of Ionic Compounds
2 x +3 = +6
3 x -2 = -6
Al2O3
Al3+
1 x +2 = +2
Ca2+
1 x +2 = +2
Na+
O22 x -1 = -2
CaBr2
Br1 x -2 = -2
Na2CO3
CO32-
NH4+Br-
Ca+2Cl-2
Na+C2H3O2-
Cu+2SO4K+HCO3Ba+2(NO3-)2
Zn+2S-2
Li+3PO4-3
Al+3(HSO4-)3
Fe+3 2O-2 3
Zn+2CO3-2
H+CN-
Ag+ 2 Cr2O7 -2
Fe+3PO3 -3
H2+ O2-2
Ca+2 HPO4-2
Cu+NO2Cu+2 (NO2- )2
Hg+2C2O4-2
Cr+3(OH- )3