isotopes and atomic mass 2019.notebook...isotopes and atomic mass 2019.notebook 3 november 21, 2019...
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Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
Nov 168:43 AM
Isotope 1 Isotope 2
Properties of Isotope 1Atomic #: 6Mass: 12 amuColor: Blackish-grayLuster: None/DullHardness: BrittleRadioactivity: Stable. Geiger counter does not detect radiation.
1. What element is Isotope 1? What element is Isotope 2?
2. How did you identify the above elements?
3. What is different for the two isotopes?
DO NOW
Properties of Isotope 2Atomic #: 6Mass: 14 amuColor: Blackish-grayLuster: None/DullHardness: BrittleRadioactivity: Unstable. Geiger counter detects radiation.
Nov 168:43 AM
Isotope 1 Isotope 2
Properties of Isotope 1Atomic #: 6Mass: 12 amuColor: Blackish-grayLuster: None/DullHardness: BrittleRadioactivity: Stable. Geiger counter does not detect radiation.
1. What element is Isotope 1? What element is Isotope 2?They are both Carbon
2. How did you identify the above elements?The given atomic number is 6.
3. What is different for the two isotopes?The mass number; the level of radioactiviyt.
DO NOW
Properties of Isotope 2Atomic #: 6Mass: 14 amuColor: Blackish-grayLuster: None/DullHardness: BrittleRadioactivity: Unstable. Geiger counter detects radiation.
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
Nov 168:43 AM
Isotopes and Atomic Mass
Aim: What is an isotope? How is atomic mass calculated?
http://www.brainpop.com/science/matterandchemistry/isotopes/
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Nov 168:43 AM
Isotope: two of the same element with a different mass number, due to a different number of neutrons.
Isotopes must always have the SAME atomic number to be the same element.
12
C6
14
C6
6 p6 n
6 p8 n
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
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Isotope Notations
C-14
14C
Carbon – 14
Nov 168:43 AM
Isotope Notations
C-14
14C
Carbon – 14 The number in the notation always represents the mass number of the isotope.
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
Nov 168:43 AM
Determine the number of protons, neutrons and electrons in each of the following isotopes: 16O Oxygen-18 O-15
Isotopes can and will have a different mass number from the mass of the periodic table.
Question: What is the mass number of the most abundant isotope of oxygen?
Nov 168:43 AM
Determine the number of protons, neutrons and electrons in each of the following isotopes:
16O Oxygen-18 O-15
15.994 = 16 amu
mass #= 16 mass #= 18 mass #= 15atomic #= 8 atomic #= 8 atomic #= 8protons= 8 p protons= 8 p protons= 8 pneutrons= 8 n neutrons= 10 n neutrons= 7 nelectrons= 8e- electrons= 8e- electrons= 8e-
Isotopes can and will have a different mass number from the mass of the periodic table.
Question: What is the mass number of the most abundant isotope of oxygen?
The most abundant isotope of oxygen is Oxygen-16.
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
Nov 168:43 AM
Why is the atomic mass not a whole number?
Nov 168:43 AM
Why is the atomic mass not a whole number?
Every element has different isotopes that occur naturally on Earth. Some isotopes are more abundant, "common" than others.
Atomic mass: a weighted average that uses the percent abundance and mass of all naturally occurring isotopes.
Carbon-12 abundance= 99.0 %Carbon-13 abundance= 1.0 %
The weighted average of the isotopes mass should be closer to the MORE abundant isotope.
Isotopes and Atomic Mass 2019.notebook
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Nov 1310:58 AM
Ex 1) Find the atomic mass of Carbon:
Percent Isotope Abundance12C 99 % 13C 1 %
Nov 1310:58 AM
Ex 1) Find the atomic mass of Carbon:
Percent Isotope Abundance12C 99 % 13C 1 %
To find atomic mass:1) Convert the % abundance to a decimal abundance (divide by 100)
2) Multiply the mass of the isotope by its' decimal abundance.
3) Add the resulting values together.averageatomic mass= (12)(0.99) + (13)(0.01) 99% of 12 1% of 13averageatomic mass= 11.88 + 0.13
averageatomic mass= 12.01 amu
Closest to the Carbon-12 mass, the more abundant isotope.
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
1. Based on the natural abundances and mass of the isotopes, find the average atomic mass of Neon.
2. To which Neon isotope should the average atomic mass be closest to?
1. Based on the natural abundances and mass of the isotopes, find the average atomic mass of Neon.
2. To which Neon isotope should the average atomic mass be closest to?
(19.99)(0.909) + (20.99)(.003) + (21.00)(.088)= 20.169 amu
It will be closest to Ne-20, the more abundant isotope.
Isotopes and Atomic Mass 2019.notebook
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November 21, 2019
Nov 168:43 AM
Isotope 1 Isotope 2
Nucleus of Isotope 1 Nucleus of Isotope 2
Summary Questions
Properties of Isotope 1Atomic #: 6Mass: 12 amu
Properties of Isotope 1Atomic #: 6Mass: 14 amu
1.) Explain in terms of subatomic particles, why isotope 1 and isotope 2 have a difference mass number?
2.) Explain in terms of subatomic particles, how the two isotopes represent the same element?
Nov 168:43 AM
Isotope 1 Isotope 2
Nucleus of Isotope 1 Nucleus of Isotope 2
Summary Questions
Properties of Isotope 1Atomic #: 6Mass: 12 amu
Properties of Isotope 1Atomic #: 6Mass: 14 amu
1.) Explain in terms of subatomic particles, why isotope 1 and isotope 2 have a difference mass number?Isotope 1 and 2 have a different mass number because their nuclei each contain a different number of neutrons.2.) Explain in terms of subatomic particles, how the two isotopes represent the same element?The two isotopes represent the same element because their nuclei each contain the same number of protons.