© 2014 Pearson Education, Inc. Chapter 6 Lecture Basic Chemistry Fourth Edition Chapter 6 Ionic and...
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© 2014 Pearson Education, Inc. Chapter 6 Lecture Basic Chemistry Fourth Edition Chapter 6 Ionic and Molecular Compounds 6.1 Ions: Transfer of Electrons Learning Goal Write the symbols for the simple ions of the representative elements.
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Transcript of © 2014 Pearson Education, Inc. Chapter 6 Lecture Basic Chemistry Fourth Edition Chapter 6 Ionic and...
© 2014 Pearson Education, Inc.
Chapter 6 Lecture
Basic ChemistryFourth Edition
Chapter 6 Ionic and Molecular Compounds6.1 Ions: Transfer of Electrons
Learning Goal Write thesymbols for the simple ions ofthe representative elements.
© 2014 Pearson Education, Inc.
Chapter 6 Readiness
Key Math Skills• Using Positive and Negative Numbers in
Calculations (1.4B)• Solving Equations (1.4D)Core Chemistry Skills• Writing Electron Configurations (5.4)• Drawing Electron-Dot Symbols (5.6)
© 2014 Pearson Education, Inc.
Compounds
Most elements except for noble gases are found in nature combined with other elements in compounds.
Compounds form when electrons are transferred or shared to give a stable electron configuration to both atoms.
© 2014 Pearson Education, Inc.
Compounds
Atoms lose, gain, or share electrons in the form of an ionic bond or covalent bond to obtainan octet.•Ionic bonds are formed when the valence electrons of a metal are transferred to atoms of nonmetals.•Covalent bonds are formed when atoms of nonmetals share their valence electrons.
© 2014 Pearson Education, Inc.
Ionic and Molecular Compounds
© 2014 Pearson Education, Inc.
Ionic and Molecular Compounds
© 2014 Pearson Education, Inc.
Positive Ions: Loss of Electrons
Ions, which have electrical charges, form when atoms lose or gain electrons to form a stable electron configuration.
•Because ionization energies of metals inGroup 1A (1), 2A (2), and 3A (13) are low, metal atoms lose their valence electrons, forming ions with a positive charge.
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Positive Ions: Loss of Electrons
A sodium atom (Na) will lose its 3s1 electron to form a sodium ion (Na+).
Positively charged ions of metals are called cations.
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Positive Ions: Loss of Electrons
Magnesium, a metal in Group 2A (2), obtainsa stable electron configuration by losing twovalence electrons, forming an ion with a2+ charge.
© 2014 Pearson Education, Inc.
Negative Ions: Gain of Electrons
The ionization energy of a nonmetal atom in Groups 5A (15), 6A (16), and 7A (17) is high.
Rather than lose electrons to form ions, a nonmetal atom will gain one or more electrons to obtain a stable electron configuration.
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Negative Ions: Gain of Electrons
An atom of chlorine with seven valence electrons gains one electron to form an octet. Because it now has 18 electrons and not17 electrons, it becomes a chloride ion (Cl−)with a charge of 1−.
Negatively charged ions of nonmetals are called anions.
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Formula and Names of Some Common Ions
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Learning Check
Select the correct answer for aluminum.
A. The electron change to obtain an octet is _____.
(1) loss of 3 e− (2) gain of 3 e− (3) gain of 5 e −
B. The charge of the aluminum ion is _____.
(1) 3− (2) 5− (3) 3+
C. The symbol for the aluminum ion is _____.
(1) Al3+ (2) Al3– (3) Al+
© 2014 Pearson Education, Inc.
Solution
Select the correct answer for aluminum.
A. The electron change to obtain an octet is _____. (1) loss of 3 e−
B. The charge of the aluminum ion is _____.
(3) 3+
C. The symbol for the aluminum ion is _____.
(1) Al3+
© 2014 Pearson Education, Inc.
Ionic Charges from Group Numbers
We can use group numbers of representative elements in the periodictable to determine their charges.
Group Number
Ion Charge
Group 1A (1) 1+
Group 2A (2) 2+
Group 3A (13) 3+
Group 5A (15) 3−
Group 6A (16) 2−
Group 7A (17) 1−
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Common Ions and Their NearestNoble Gases
Atoms lose or gain electrons to become like their nearest noble gas.
© 2014 Pearson Education, Inc.
Learning Check
Select the correct answer for sulfur.
A. The group number for sulfur is _____.
B. The number of valence electrons in sulfuris ____.
C. The change in electrons for an octet requires a
(1) loss of 2 e− (2) gain of 2 e− (3) gain of 4 e−
D. The ionic charge of a sulfide ion is _____.
(1) 2+ (2) 2− (3) 4−
© 2014 Pearson Education, Inc.
Solution
Select the correct answer for sulfur.
A. The group number for sulfur is 6A (16).
B. The number of valence electrons in sulfuris six.
C. The change in electrons for an octet requires a
(2) gain of 2 e−
D. The ionic charge of a sulfide ion is _____.
(2) 2−
© 2014 Pearson Education, Inc.
Chemistry Link to Health, Ions
Several ions in body fluids have important physiological and metabolic functions.
