Atoms, Molecules, & Ions
Atom
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Molecules and Ions
Compounds made up of two or more atoms held together by either:
1. ________________________________________________
2. ________________________________________________
Covalent: __________________________; leads to the formation of
________________.
Take a water molecule, H2O, for example:
Each H shares its electron with the O, so that the O has two
shared electrons, completing its valence shell.
A molecule acts as a unit by itself. It moves together.
To represent a molecule, you can use either:
Ball-and-stick model
Space filling model
Ionic: ________________; leads to the formation of ____________.
Consider NaCl
Chlorine has a higher affinity for electrons than sodium, and so
it takes one away from sodium
The electron joins up with the chlorine, and becomes a
negatively charged ion (“_________”)
Cl + e –  Cl –
The sodium atom gives off an electron and becomes a
positively charged ion (“_________”) in the process
Na  Na+ + e –
Since these charges have opposite signs, they attract. The
positive Na+ and the negative Cl- form a ________________, also
called a salt.
NOTE:
A salt refers to any ionic solid, not just our example of table salt.
Anion: _____________________________________. Ex. Cl-, SO4-2
Cation: ____________________________________. Ex. Al+3, NH4+
Monotomic: ________________________________. Ex. Ne, He, Li+
Diatomic: ______________________________________________
_____________________________________. Ex. O2, IBr, NO, ClOTriatomic: _________________________________. Ex. O3, NO2, I3Polyatomic: _____________________________________________
_______________________________ Ex. H3PO4, HCl, N2O, HSO4-
HW p.68 #1
Formulas and Names of Ionic Compounds
When Given Name, Write the Formula
The rules to follow are:
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


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Write the formula for magnesium chloride.
Write down the Mg2+ and Cl1- right next to each other,
as in this image:
Move the positive charge (dropping the sign) to the
subscript position of the anion:
Move the negative charge (dropping the sign) to the subscript
position of the cation:
The result of all this moving is:
Since subscripts of one are not written, but understood to be present,
the final answer is:
Write the formula for:
calcium bromide
potassium iodide
barium oxide.
gold (III) bromide.
iron (IV) chloride.
tin (II) carbonate.
ammonium sulphate.
When Given Formula, Write the Name
1. The name of the metal (cation) is first.
Ex: NaCl, Sodium chloride
2. The name of the non-metal (anion) has -ide added
Ex: NaCl, Sodium chloride
** see below for polyatomic **
3. If the metal has more than one possible charge (transition element)
Uncross to determine the metal’s charge
For example
AgO
Pb(CO3)2
With the Stock Method, you must indicate which ion using the
charge in roman numerals
Ex: FeCl2, Iron (II) chloride
Alternatively, the Common Name may be used if the metal has more
than one possible ion.
Latin root and then add
Ex:
-ous for the lower charge
-ic for the higher charge
FeCl2, Ferrous chloride
FeCl3, Ferric chloride
Polyatomic ions:
a. Positive charged (CATION) species on left.
b. Negative charged (ANION) species on right
Use name/s of polyatomic ion DO NOT CHANGE IT!!!! OR
anion ending in –ide
Formula
BaSO4
Ions
Ba+2 and SO42-
NH4NO2
NH4+1 and NO21- Ammonium nitrite
Fe(NO3)2
Fe+2 and NO31-
Compound
Mg(OH)2
Name
barium sulfate
iron (II) nitrate or
ferrous nitrate
Stock Name
Iron (III) oxide
(NH4)2SO4
Sodium hypochlorite
Calcium fluoride
Ca(HCO3)2
Potassium binoxalate
Exercises p. 71 #4 a-k; p. 72 #5 a-k
Naming hydrates:
When a crystal of an inorganic molecule is grown by evaporation,
frequently it is found that the crystal structure will include water
molecules.
Molecules/Ionic Solid that include water are called _____________.
Use a prefix to represent how many water molecules are attached.
Prefix Used
# of water
molecules
1
2
3
4
5
Prefix Used
For Example:
Iron (III) phosphate octahydrate
Nickel (II) chloride hexahydrate
Calcium nitrate tetrahydrate
Na2SO4 · 10H2O
Mg3(PO4)2· 7H2O
Ni3(PO4)2 · 8H2O
Exercises p.
73 #6 & 7 Hand-in #3
71 #4 o-t; p. 72 #5 o-t
# of water
molecules
6
7
8
9
10
Formulas and Names of Covalent Compounds
Follow the following rules when naming Molecular Compounds:
1. Elements to the left side of the periodic table are named first.
2. Add the -ide ending to the second element
3. Use Greek prefixes for number of atoms:
mono
di
tri
tetra
penta
1
2
3
4
5
hexa
hepta
octa
nona
deca
Note:
Never use “mono” for the first element!
tetraphosphorus trisulphide
trisilicon tetranitride
oxygen diflouride
BrF
S4N2
P2O6
Exercises p. 74 #8 & 9
Exercises p. 75/6 #14 – 162 every 2nd one
6
7
8
9
10
ACIDS
A compound is called an ACID if the compound has a chemical
formula starting with “____”.
Here is a list of some common acids:
__________ = ________________
__________ = ________________
__________ = ________________
__________ = ________________
__________ = ________________
Some properties of acids:
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Bases
A compound is called an Base if the compound has a chemical
formula ends with an “______”
A few common bases are:
__________ = ________________
__________ = ________________
Some properties of bases:
-
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Counting Atoms
When we are given a molecule, it’s easy to count how many atoms
are present.
For Example:
a. AgNO3(s)
b. KCl(aq)
c. Pb(SO4)2(s)
d. 2 Al(CH3COO)3(s)
Exercises p. 75/6 #14 – 163 every 2nd one