### Wednesday, September 5

```Homework from page 104
Homework from page 104
15. Boron has two isotopes.
boron-10
mass = 10.013 amu
abundance = 19.8%
Boron-11
mass = 11.009 amu
abundance = 80.2%
Calculate its atomic mass.
Homework from page 104
(mass x abundance) + (mass x abundance)
boron-10
mass = 10.013 amu
abundance = 19.8%
Boron-11
mass = 11.009 amu
abundance = 80.2%
Homework from page 104
(mass x abundance) + (mass x abundance)
boron-10
mass = 10.013 amu
abundance = 19.8%
Boron-11
mass = 11.009 amu
abundance = 80.2%
Homework from page 104
(mass x abundance) + (mass x abundance)
10.013 amu
x
19.8%
11.009 amu
x
80.2%
Homework from page 104
(mass x abundance) + (mass x abundance)
10.013 amu
x
.198
11.009 amu
x
.802
Homework from page 104
(mass x abundance) + (mass x abundance)
10.013 amu
x
.198
1.983
11.009 amu
x
.802
8.929
Homework from page 104
(mass x abundance) + (mass x abundance)
10.013 amu
x
.198
1.983
11.009 amu
x
.802
8.829
Homework from page 104
(mass x abundance) + (mass x abundance)
1.983
+ 8.829
Homework from page 104
(mass x abundance) + (mass x abundance)
1.983
+ 8.829
10.812 amu
Homework from page 104
(mass x abundance) + (mass x abundance)
1.983
+ 8.829
10.812 amu
Homework from page 104
16.Helium has two naturally
occurring isotopes, helium-3
and helium-4.
The atomic mass of helium is
4.003 amu.
Which isotope is more
abundant in nature?
Homework from page 104
16.Helium has two naturally
occurring isotopes, helium-3
and helium-4.
The atomic mass of helium is
4.003 amu.
Which isotope is more
abundant in nature?
Homework from page 104
17.Calculate the atomic mass of
magnesium. Three isotopes are:
mass = 23.985 amu, abund. = 78.99%
mass = 24.986 amu, abund. = 10.00%
mass = 25.982 amu, abund. = 11.01%
Homework from page 104
(mass x abundance)
mass = 23.985 amu, abund. = 78.99%
mass = 24.986 amu, abund. = 10.00%
mass = 25.982 amu, abund. = 11.01%
Homework from page 104
(mass x abundance)
23.985 x 78.99%
24.986 x 10.00%
25.982 x 11.01%
Homework from page 104
(mass x abundance)
23.985 x .7899
24.986 x .1000
25.982 x .1101
Homework from page 104
(mass x abundance)
23.985 x .7899 = 18.95 amu
24.986 x .1000 = 2.498 amu
25.982 x .1101 = 2.861 amu
Homework from page 104
(mass x abundance)
18.95 amu
2.498 amu
+ 2.861 amu
Homework from page 104
(mass x abundance)
18.95 amu
2.498 amu
+ 2.861 amu
24.31 amu
Homework from page 104
(mass x abundance)
18.95 amu
2.498 amu
+ 2.861 amu
24.31 amu
Homework from page 104
21. Nitrogen has two naturally
occurring isotopes, N-14 and
N-15.
The atomic mass of nitrogen
is 14.007 amu.
Which isotope is more
abundant in nature?
Homework from page 104
21. Nitrogen has two naturally
occurring isotopes, N-14 and
N-15.
The atomic mass of nitrogen
is 14.007 amu.
Which isotope is more
abundant in nature?
Daily Quiz
Daily Quiz
1. What element has 47 protons?
A. iron (Fe)
B. silver (Ag)
C. titanium (Ti)
D. platinum (Pt)
E. uranium (U)
Daily Quiz
2. What element has 12 electrons?
A. magnesium (Mg)
B. beryllium (Be)
C. chromium (Cr)
D. phosphorus (P)
E. carbon (C)
Daily Quiz
3. How many neutrons are in
helium?
A.
B.
C.
D.
E.
1
2
3
4
5
Daily Quiz
4. How many protons are in
sodium?
A.
B.
C.
D.
E.
1
3
11
12
23
Daily Quiz
4. How many electrons are in
neon?
A.
B.
C.
D.
E.
1
8
10
18
20
Daily Quiz
5. How many neutrons are in
carbon?
A.
B.
C.
D.
E.
2
4
6
8
12
Daily Quiz
1. What element has 47 protons?
A. iron (Fe)
B. silver (Ag)
C. titanium (Ti)
D. platinum (Pt)
E. uranium (U)
Daily Quiz
1. What element has 47 protons?
A. iron (Fe)
B. silver (Ag)
C. titanium (Ti)
D. platinum (Pt)
E. uranium (U)
Daily Quiz
2. What element has 12 electrons?
A. magnesium (Mg)
B. beryllium (Be)
C. chromium (Cr)
D. phosphorus (P)
E. carbon (C)
Daily Quiz
2. What element has 12 electrons?
A. magnesium (Mg)
B. beryllium (Be)
C. chromium (Cr)
D. phosphorus (P)
E. carbon (C)
Daily Quiz
3. How many neutrons are in
helium?
A.
B.
C.
D.
E.
1
2
3
4
5
Daily Quiz
4. How many protons are in
sodium?
A.
B.
C.
D.
E.
1
3
11
12
23
Daily Quiz
4. How many electrons are in
neon?
A.
B.
C.
D.
E.
1
8
10
18
20
Daily Quiz
5. How many neutrons are in
carbon?
A.
B.
C.
D.
E.
2
4
6
8
12
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