1. Atoms, Molecules and Ions Atomic Theory of Matter
John Dalton
1806
1. Matter consists of indivisible atoms
All atoms of a given element
have identical properties
Different elements have atoms that
differ in mass
4. Atoms are indestructible and chemical
reactions are a rearrangement of atoms
5. Compounds contain a definite and small number
of atoms

2. 1. Matter consists of indivisible atoms
electrons
protons
neutrons
subatomic particles
electrons
charge =
-1.60 x C
= -1
mass
= 9.1 x kg
protons
charge
= +1
mass
= x kg
neutrons
charge
= 0
mass
= x kg

3. 1. Matter consists of indivisible atoms
nucleus
= protons + neutrons
electrons
move around the nucleus
electron “cloud”
= volume of atom
average diameter of atom
10-10 m
= ångström (Å)

4. ? = Z # protons = # e- 2. All atoms of a given element
have identical properties X A Z ?
not exactly
atoms of an element
= same number of protons
atomic number
= Z
Z = 6
= C
carbon 6C
6 e-
Z = 30
= Zn
zinc
30Zn
30 e-
elements
neutral
# protons =
# e-
elements
different # neutrons
proton + neutron = A
= mass number

5. Ar 40 18 2. All atoms of a given element have identical properties X AZ
element can have
isotopes
7 nuclides of C
carbon
Z = 6 6C 12
most abundant
6 neutrons
Carbon-14 dating C 14 6
6 protons + 8
neutrons
What is the symbol for a nuclide that contains
22 neutrons and 18 protons? Ar 40 18

6. 4. Atoms are indestructible and chemical
reactions are a rearrangement of atoms
reactions
valence electrons
valence e-
= Group number 1 8 2 3 4 5 6 7

7. elements arranged by atomic number column group chemical properties1 2 3 4 5 6 7 8
elements arranged by
atomic number
column
group
chemical properties
row
period

8. Noble gases Alkali metals unreactive 8 valence electrons
(He 2 valence e-)
monatomic gases
Alkali metals
soft solids
very, very reactive
1 valence electron
lose 1 electron Na
( protons,
e-) 11 11
Na ( protons, e-) 11 + 10
cation

9. Alkaline earth metals solids reactive 2 valence electrons
lose 2 electrons Sr
Sr2+
conduct heat,
electricity
solids
(Hg)
lose e-
non-metals
metals

10. Non-metals = metalloids poor conductors solids, liquids, gases Group 7
Si 14
C 6
B 5
N 7
O 8
F 9
P 15
S 16
Cl 17
As33
Se34
Br35
Te52
I 53
At85 3 4 5 6 7
= metalloids
poor conductors
solids, liquids, gases
Group 7
halogens X2
very reactive
7 valence electrons
gain 1 electron
Cl ( protons, e-) 17 17
Cl ( protons, e-) 17 - 18
anion
non-metals
gain electrons

11. doesn’t fit anywhere lose e- H ( proton, e-) 1 1 H ( proton, e-) 1 ++
gain e-
proton
H ( proton, e-) 1
H ( proton, e-) 1 2 -
hydride

12. Ionic solids cation + anion + - metal non-metal sodium + chlorine NaCl
5. Compounds contain a definite and small number
of atoms
Ionic solids
cation
+ anion + -
metal
non-metal
sodium +
chlorine
NaCl
sodium
chloride Na Cl + -
801o C
lithium +
oxygen
Li O
lithium
oxide Li O 2 + 2-
> 1700oC
magnesium +
nitrogen
Mg N
magnesium
nitride Mg N 2+ 3- 3 2
strong interactions
(ion-ion)
high melting points

13. Transition metals
more than 1 form
except
Ag+
Zn2+
Cd2+
Al3+
aluminum
manganese +
oxygen +
sulfur Al
Mn1+
Mn2+
Mn3+
Mn4+ S 3+ 2-
Al S 2 3
aluminum sulfide
Mn3+ O 2-
Mn2O3
Mn4+
O2-
MnO2
manganese (III) oxide
manganese (IV) oxide

14. share valence electrons = chemical bonds carbon + chlorine C Cl 4+ -
Covalent compounds
non-metal +
non-metal
share valence electrons
= chemical bonds
carbon +
chlorine
mono di
tri
tetra
penta
hexa
hepta
octa C Cl 4+ -
CCl4
carbon
tetra
chloride
nitrogen +
oxygen N ? O 2- NO
nitrogen monoxide 2+
NO2
nitrogen dioxide 4+
N2O4
dinitrogen
tetroxide 4+

15. Covalent compounds N H
NH3
nitrogen
trihydride
ammonia 3+ 1- H O
H2O
dihydrogen
monoxide
water 1+ 2-
weak forces
low m.p.
0.0oC
Table 2.5 p. 62
Polyatomic ions
NH4+
ammonium
ClO3-
chlorate
OH-
hydroxide
MnO4-
permanganate
NO3-
nitrate
CrO42-
chromate
SO42-
sulfate
CO32-
carbonate
PO43-
phosphate