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Ionic & Molecular Compounds
Ionic & Molecular Compounds
Ionic & Molecular Compounds
Ionic & Molecular Compounds
Valence ElectronsSusan BairdDori Delaney
Cindy Rothwell
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Ionic & Molecular Compounds
Valence Electrons
Valence electrons are the electrons in the outermost energy shell.
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Ionic & Molecular Compounds
Valence Electrons
Valence electrons are the electrons in the outermost energy shell.
The number of valence electrons equals the A Group number for the element on the periodic table.
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Ionic & Molecular Compounds
Valence Electrons
Examine the Periodic Table
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Ionic & Molecular Compounds
Valence Electrons
Examine the Periodic TableDid you notice that the group numbers are labeled with two different sets of numbers?
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Ionic & Molecular Compounds
Valence Electrons
Examine the Periodic TableDid you notice that the group numbers are labeled with two different sets of numbers?The upper numbers from 1 to 18 are the IUPAC Group numbers.
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Ionic & Molecular Compounds
Valence Electrons
Examine the Periodic Table
Did you notice that the group numbers are labeled with two different sets of numbers?
The upper numbers from 1 to 18 are the IUPAC Group numbers.
The lower numbers from 1A to 8A are the Main Group Numbers.
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Ionic & Molecular Compounds
Valence Electrons
Group 1A Group 6A Group 7A Group 8A
Li O F Ne1 valence 6 valence 7 valence 8 valenceelectron electrons electrons electrons
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Ionic & Molecular Compounds
Valence Electrons
Let’s try an example:How many valence electrons does carbon have?Examine the periodic table and find Carbon’s Main Group number.
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Ionic & Molecular Compounds
Valence Electrons
Let’s try an example:
How many valence electrons does carbon have?
Examine the periodic table and find Carbon’s Main Group number.
Carbon is in Group 4A.
Therefore carbon has 4 valence electrons.Return to Home Page
Ionic & Molecular Compounds
Valence Electrons
Now it’s your turn: periodic tableHow many valence electrons do each of the following elements contain?KSAlBr
Answers are on the next page.Return to Home Page
Ionic & Molecular Compounds
Valence Electrons
Answers: periodic tableHow many valence electrons do each of the following elements contain?K is in Group 1A so it has 1 valence e-.S is in Group 6A so it has 6 valence e-.Al is in Group 3A so it has 3 valence e-.Br is in Group 7A so it has 7 valence e-.
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Ionic & Molecular Compounds
Valence Electrons
When elements form bonds with other elements they gain, lose or share electrons to obtain a full valence shell.
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Ionic & Molecular Compounds
Valence Electrons
When elements form bonds with other elements they gain, lose or share electrons to obtain a full valence shell.
An element with a full valence shell is in its most stable form.
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Ionic & Molecular Compounds
Valence Electrons
A full valence shell consists of 8 electrons for most elements.
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Ionic & Molecular Compounds
Valence Electrons
A full valence shell consists of 8 electrons for most elements.
The Octet Rule states that atoms gain, lose or share electrons to obtain 8 valence electrons.
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Ionic & Molecular Compounds
Valence Electrons
Most atoms follow the octet rule.
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Ionic & Molecular Compounds
Valence Electrons
Most atoms follow the octet rule.
Hydrogen and Helium are two exceptions.
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Ionic & Molecular Compounds
Valence Electrons
Most atoms follow the octet rule.Hydrogen and Helium are two exceptions.The first shell of electrons is so small that it can only hold two electrons.
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Ionic & Molecular Compounds
Valence Electrons
Most atoms follow the octet rule.
Hydrogen and Helium are two exceptions.
The first shell of electrons is so small that it can only hold two electrons.
Therefore H gains, loses or shares one electron to have a full (or empty) valence shell.
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Ionic & Molecular Compounds
Valence Electrons
Watch this video to see how valence electrons are involved in bonding.
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Ionic & Molecular Compounds
Valence Electrons
To discover more about the role that valence electrons play in bond formation go to the Ionic Bonding or Covalent Bonding pages.
To see how valence electrons are represented in short hand notation go to the Lewis Dot Structure page.
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