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1
Properties of the Three Key Subatomic Particles
Charge
Mass
Location
Name(Symbol) Relative Absolute(C)* Relative(amu)† Absolute(g) in the Atom
Proton (p+)
Neutron (n0)
Electron (e-)
1+ +1.60218x10-19
1.00727
1.67262x10-24 Nucleus
0
0
1.00866
1.67493x10-24 Nucleus
1-
-1.60218x10-19
0.00054858
1 amu = 1.66 x 10-24 g
9.10939x10-28
Outside
Nucleus
General Features of the Atom
Atomic Symbols, Isotopes,
Numbers
A
J
Z
The Symbol of the Atom or Isotope
J = Atomic symbol of the element
A = mass number; A = Z + N
Z = atomic number
(the number of protons in the nucleus)
N = number of neutrons in the nucleus
Isotope = atoms of an element with the same
number of protons, but a different number
of neutrons
What makes up the mass of an atom?
Calculate the mass of an atom of 19F from the masses of the
protons, neutrons and electrons.
9 protons: 9 x 1.007 amu
= 9.063 amu
10 neutrons: 10 x 1.009 amu
= 10.09 amu
9 electrons: 9 x 0.0005486 amu = 0.004937 amu
= 19.16 amu
Compared to an “official” value of 18.998 amu
?????????
Complete the table
Symbol
37Cl
131I
23Na+
1H
18O2-
# p+
# n0
17
20
53
78
# e-
17
Mass #
37
53
131
11
12
10
23
1
0
1
1
8
10
10
18
Comparison to the earth
• The earth has a mass of 6.0 x 1024 kg and a
radius of 6400 km.
• What is the density of the earth in g/cm3?
• If the earth were to be compressed so that it had
the same density as a gold nucleus, (2.9 x 1012
g/cm3) what radius would it have?
Solutions
3
10 g
27
Mass  6.0 x 10 kg x
 6.0 x 10 g
1 kg
24
 105 cm 
  6400 x 105 cm  6.4 x108 cm
r  6400 km x 
 1 km 


3
4 3 4
8
Volume  r   6.4 x10 cm 1.098 x1027 cm 3
3
3
27
6.0 x 10 g
3
density  m / V 
 5.5 g / cm
3
1.098 x 1027 cm
Solutions cont’d
Let d  2.9 x10 g / cm
12
3
27
m
6
.
0
x
10
g
12
3
d  2.9 x 10 g / cm  
V
V
m
6.0 x 1027 g
15
3
V 

2
.
069
x
10
cm
d 2.9 x 1012 g / cm 3
4
3V
3
V  r 3 r 

3
4
r
3
(3) x (2.069 x1015 cm 3 )
 79000 cm  0.79 km
4
Tools of the Laboratory
Figure B2.2
The Mass Spectrometer and Its
Data
Figure 24.2
A plot of neutrons vs. protons for the stable nuclides.
12
Periodic Table
Elements that occur as molecules.
Figure 2.16
1A
2A
3A
4A
5A
6A
7A
8A
(1)
(2)
(13)
(14)
(15)
(16)
(17)
(18)
N2
O2
F2
P4
S8
Cl2
Se8
Br2
H2
I2
diatomic molecules
tetratomic molecules
octatomic molecules
Figure 2.19
Some common monatomic ions of the
elements.
Can you see any patterns?
Table 2.5 (partial) Some Common Polyatomic Ions
Formul
a
NH4
+
Name
Formula
Name
H3O+
hydronium
Cations
ammonium
Common Anions
CH3COO-
acetate
CO3-2
carbonate
CN-
cyanide
chromate
OH-
CrO4-2
hydroxide
Cr2O7-2
dichromate
ClO3-
chlorate
O-2
oxide
NO2-
nitrite
SO4-2
sulfate
NO3-
nitrate
PO4-3
phosphate
MnO4-
permanganate
Prefixes (Greek)
• One (1)
mono• Two (2)
di• Three (3)
tri• Four (4)
tetra• Five (5)
penta• Six (6)
hexa• Seven (7)
hepta• Eight (8)
octa• Nine (9)
nona• Ten (10)
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