Chapter 8 Periodic Properties of the Elements...5 Ions of d-Block Elements Ions of d-block elements...
Transcript of Chapter 8 Periodic Properties of the Elements...5 Ions of d-Block Elements Ions of d-block elements...
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Chapter 8
Periodic Properties of the Elements
Objectives
Periodic Trends in Properties of Elements• Electron Affinity• Metallic Characteristics
Electron Configuration of Ions• Ions of Main Group Elements• Ions of d-Block Elements
Ionic Radius• Comparing Ionic Radius with Atomic Radius• Isoelectronic Series
Electron Affinity
Electron affinity (EA) :
Why is the energy negative?
Why is it important to remember stability of an atom?
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Electron Affinity
Which atom is most likely to accept an electron? Why?-Define isoelectronic:
Electron Affinity (2)
How does electron affinity change across a periodic table?
Ionic Radius
The ionic radius is the radius of a cation or an anion.
Cations:
-what happens to effectivenuclear charge? Whathappens to the radius andwhy?
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Ionic Radius
The ionic radius is the radius of a cation or an anion.
Anions:
-what happens to effectivenuclear charge and why? What happens to the radiusand why?
Notes
Metallic Character
Metals tend toØ Be shiny, lustrous, malleable, and ductile
Ø Be good conductors of both heat and electricity
Ø Have low ionization energies (commonly form cations)
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Metallic Character (2)Nonmetals tend toØ Vary in color and are not shiny
Ø Be brittle, rather than malleable
Ø Be poor conductors of both heat and electricity
ØHave high electron affinities (commonly form anions)
Metallic Character (3)
Metalloids are elements with properties intermediate between those of metals and nonmetals.
Electron Configurations of Ions
To write the electron configuration of an ion formed by a main group element:
1) Write the configuration for the atom.
2) Add or remove the appropriate number of electrons.
Na: 1s22s22p63s1 Na+: 1s22s22p6
10 electrons total, isoelectronic with Ne
Cl: 1s22s22p63s23p5 Cl− : 1s22s22p63s23p6
18 electrons total, isoelectronic with Ar
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Ions of d-Block Elements
Ions of d-block elements are formed by removing electrons first from the shell with the highest value of n.
For Fe to form Fe2+, two electrons are lost from the 4s subshell not the 3d.
Fe: [Ar]4s23d 6 à Fe2+: [Ar]3d 6
Fe can also form Fe3+, in which case the third electron is removed from the 3d subshell.
Fe: [Ar]4s23d 6 à Fe3+: [Ar]3d 5
Objectives
Periodic Trends in Properties of Elements• Electron Affinity• Metallic Characteristics
Electron Configuration of Ions• Ions of Main Group Elements• Ions of d-Block Elements
Ionic Radius• Comparing Ionic Radius with Atomic Radius• Isoelectronic Series