Slide 1 of 31 Periodic Trends 6.3

© Copyright Pearson Prentice Hall Slide 2 of 31 Periodic Trends Sodium chloride (table salt) produced the geometric pattern in the photograph. Such a pattern can be used to calculate the position of nuclei in a solid. You will learn how properties such as atomic size are related to the location of elements in the periodic table. 6.3

© Copyright Pearson Prentice Hall Periodic Trends > Slide 3 of 31 Trends in Atomic Size What are the trends among the elements for atomic size? 6.3

Slide 4 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Atomic Size The atomic radius is one half of the distance between the nuclei of two atoms of the same element when the atoms are joined. 6.3

Slide 5 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Atomic Size Group and Periodic Trends in Atomic Size In general, atomic size increases from top to bottom within a group and decreases from left to right across a period. 6.3

Slide 6 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Atomic Size 6.3

Slide 7 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Atomic Size 6.3

© Copyright Pearson Prentice Hall Periodic Trends > Slide 8 of 31 Ions How do ions form? 6.3

© Copyright Pearson Prentice Hall Slide 9 of 31 Periodic Trends > Ions Positive and negative ions form when electrons are transferred between atoms. 6.3

© Copyright Pearson Prentice Hall Slide 10 of 31 Periodic Trends > Ions Positive and negative ions form when electrons are transferred between atoms. 6.3

Slide 11 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Ions Some compounds are composed of particles called ions. An ion is an atom or group of atoms that has a positive or negative charge. A cation is an ion with a positive charge. An anion is an ion with a negative charge. 6.3

© Copyright Pearson Prentice Hall Slide 12 of 31 Periodic Trends > Ions Animation 7 Discover the ways that atoms of elements combine to form compounds.

© Copyright Pearson Prentice Hall Periodic Trends > Slide 13 of 31 Trends in Ionization Energy What are the trends among the elements for first ionization energy, ionic size, and electronegativity? 6.3

Slide 14 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionization Energy The energy required to remove an electron from an atom is called ionization energy. The energy required to remove the first electron from an atom is called the first ionization energy. The energy required to remove an electron from an ion with a 1+ charge is called the second ionization energy. 6.3

Slide 15 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionization Energy Group and Periodic Trends in Ionization Energy First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period. 6.3

Slide 16 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionization Energy 6.3

Slide 17 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionization Energy 6.3

© Copyright Pearson Prentice Hall Slide 18 of 31 Periodic Trends > Trends in Ionization Energy 6.3

Slide 19 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionic Size During reactions between metals and nonmetals, metal atoms tend to lose electrons, and nonmetal atoms tend to gain electrons. The transfer has a predictable effect on the size of the ions that form. 6.3

Slide 20 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionic Size Cations are always smaller than the atoms from which they form. Anions are always larger than the atoms from which they form. 6.3

Slide 21 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Ionic Size Relative Sizes of Some Atoms and Ions 6.3

© Copyright Pearson Prentice Hall Slide 22 of 31 Periodic Trends > Trends in Ionic Size 6.3 Size generally increases

Slide 23 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Electronegativity Electronegativity is the ability of an atom of an element to attract electrons when the atom is in a compound. In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period. 6.3

Slide 24 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Trends in Electronegativity Representative Elements in Groups 1A through 7A 6.3

© Copyright Pearson Prentice Hall Periodic Trends > Slide 25 of 31 Summary of Trends What is the underlying cause of periodic trends? 6.3

Slide 26 of 31 © Copyright Pearson Prentice Hall Periodic Trends > Summary of Trends The trends that exist among these properties can be explained by variations in atomic structure. 6.3

© Copyright Pearson Prentice Hall Slide 27 of 31 Periodic Trends > Summary of Trends 6.3 Atomic Size Increases Decreases Size of cationsShieldingNuclear ChargeElectronegativityIonization energySize of anionsIonic size Constant

© Copyright Pearson Prentice Hall Slide 28 of 31 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section Section Assessment 6.3

© Copyright Pearson Prentice Hall Slide 29 of Which of the following sequences is correct for atomic size? a.Mg > Al > S b.Li > Na > K c.F > N > B d.F > Cl > Br 6.3 Section Quiz

© Copyright Pearson Prentice Hall Slide 30 of Section Quiz 2. Metals tend to a.gain electrons to form cations. b.gain electrons to form anions. c.lose electrons to form anions. d.lose electrons to form cations.

© Copyright Pearson Prentice Hall Slide 31 of Section Quiz 3. Which of the following is the most electronegative? a.Cl b.Se c.Na d.I

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