Isotopes

1
Isotopes
2
Isotopes of Magnesium
12e-
12e-
12e-
24 12
25 12
26 12
Atomic symbol Mg Mg Mg
Number of protons 12 12 12
Number of electrons 12 12 12
Mass number 24 25 26
Number of neutrons 12 13 14
Isotope Notation Mg-24 Mg-25
Mg-26
Timberlake, Chemistry 7th Edition, page 64
3
Isotopes of Hydrogen
Protium
Deuterium
Tritium
(heavy hydrogen)
(radioactive hydrogen)
(ordinary hydrogen)
Ralph A. Burns, Fundamentals of Chemistry 1999,
page 100
4
Isotopes of Hydrogen

• Protium (H-1)
• 1 proton, 0 neutrons, 1 electron
• most abundant isotope
• Deuterium (H-2)
• 1 proton, 1 neutron, 1 electron
• used in heavy water
• Tritium (H-3)
• 1 proton, 2 neutrons, 1 electron
• radioactive

5
Isotopes of Three Common Elements
Mass Number
Mass (amu)
12 (exactly)
12
12 6
99.89
C
12.01
1.11
13.003
C
13 6
13
35 17
75.53
34.969
35
Cl
35.45
24.47
36.966
37
Cl
37 17
28 14
29 14
28.09
30 14
LeMay Jr, Beall, Robblee, Brower, Chemistry
Connections to Our Changing World , 1996, page
110
6
Radioisotopes

• Radioactive isotopes
• Many uses
• Medical diagnostics
• Optimal composition of fertilizers
• Abrasion studies in engines and tires

Radioisotope is injected into the bloodstream
to observe circulation.
7
Half-Life of Isotopes
Half-Lives and Radiation of Some Naturally
Occurring Radioisotopes
Isotope Half-Life
Radiation emitted
8
Atomic Structure

• ATOMS
• Differ by number of protons
• IONS
• Differ by number of electrons
• ISOTOPES
• Differ by number of neutrons

9
Formation of Cation
sodium atom Na
e-
e-
e-
e-
e-
loss of one valence electron
e-
11p
e-
e-
e-
e-
e-
e-
10
Formation of Anion
chlorine atom Cl
gain of one valence electron
e-
e-
e-
e-
e-
e-
e-
e-
17p
e-
e-
e-
e-
e-
e-
e-
e-
e-
e-
11
Formation of Ionic Bond
chloride ion Cl1-
12
Formación de cationes
Átomo de sodio Na
e-
e-
e-
e-
e-
pérdida de un Valence electrón
e-
11p
e-
e-
e-
e-
e-
e-
13
Formación de aniones
Átomo de cloro Cl
de ganancia un Valence electrón
e-
e-
e-
e-
e-
e-
e-
e-
17p
e-
e-
e-
e-
e-
e-
e-
e-
e-
e-
14
Formación de Ionic Bond
De iones de cloruro Cl1-
15
Ionic Bonding
NaCl
-
n 2
-
-
-
-
-
-
-
-
-
-
-
-
-
-

-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Na Ne3s1
Cl Ne3s23p5
Na Ne
Cl- Ne3s23p6
Transfer of electrons to achieve a stable octet
(8 electrons in valence shell).
16
Covalent Bonding
-
-
-
-
n 1
-
-
-
-
-
-
-
-

-
-
-
-
-
-
-
-
-
-
-
-
O He2s22p4
O2
O He2s22p4
Sharing of electrons to achieve a stable octet (8
electrons in valence shell).