Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy...
-
Upload
diana-mills -
Category
Documents
-
view
222 -
download
7
Transcript of Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy...
![Page 1: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/1.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Sections 23.5-23.8Metals and Metallurgy
Chemistry, The Central Science, 11th editionBrown & LeMay
![Page 2: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/2.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Physical Properties of Metals
• Metals– Conduct heat and
electricity.– Are malleable (can be
pressed or hammered into sheets).
– Are ductile (can be drawn into wire).
– Are packed so atoms can slip past each other.• So metals aren’t as brittle
as other solids.
![Page 3: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/3.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron-Sea Model
• Metals can be thought of as cations suspended in “sea” of valence electrons.
• Attractions hold electrons near cations, but not so tightly as to impede their flow.
![Page 4: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/4.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron-Sea Model
• This explains many of the properties of metals, like– Conductivity of heat
and electricity;– Deformation.
![Page 5: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/5.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Molecular Orbital Model• The electron-sea model does not explain
observed trends in melting point, boiling point, heat of fusion, etc.– The model suggests these properties should
increase with increasing number of valence electrons.
![Page 6: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/6.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Molecular Orbital Model
These trends can be explained by energy bands created by large number of molecular orbitals formed as metal atoms bond with each other.
![Page 7: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/7.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Molecular Orbital Model
• As with nonmetals, bond order apexes in center of row, then decreases.
• Thus, attractions (and melting point, etc.) apex in center of transition metals. (Group 6B)
![Page 8: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/8.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Alloys
• Alloys are mixtures of elements that have properties characteristic of metals.
• Many of the ordinary uses of metals involve alloys.
![Page 9: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/9.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Solution Alloys
• Components of alloys are dispersed uniformly—– In substitutional alloys,
solute particles take the place of solvent metal atoms.
– The particles in these alloys are quite close in size.
![Page 10: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/10.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Solution Alloys
• Components of alloys are dispersed uniformly.– In interstitial alloys, solute
particles find their way into the holes between solvent metal atoms.
– In this type of alloy the solute particles are smaller than the solvent particles.
![Page 11: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/11.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Intermetallic Compounds
• Intermetallic compounds are homogeneous alloys with definite properties and compositions.
• An example is Co5Sm,– which is used for
permanent magnets in headsets and speakers.
![Page 12: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/12.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Transition Metals
• Many important metals are included in this group.
• The transition metals are the elements in the d block of the periodic table.
![Page 13: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/13.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Physical Properties ofTransition Metals
• Some of their properties (such as ionization energy, atomic radius, etc.) are suggestive of isolated atoms.
• Others (such as density, melting point, etc.) suggest bulk solid metal.
![Page 14: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/14.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Atomic Radii
• Trends in atomic radii are similar across all three rows of transition metals.
• While Zeff increases across a row, so does the number of nonbonding electrons.– These repel each other
and increase the radius.
![Page 15: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/15.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
• Transition metals often have more than one common oxidation state.– Most have +2 state due
to loss of s electrons.– Oxidation numbers
greater than 2 are due to the loss of d electrons as well as s.
![Page 16: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/16.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
Many form compounds that have colors.
![Page 17: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/17.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
• Many have significant magnetic properties.– In diamagnetic elements, all
electron spins are paired.– Therefore, there is no net
magnetic moment.
![Page 18: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/18.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
• In paramagnetic atoms and ions, there are unpaired spins.
• The magnetic fields are randomly arranged, though, unless placed in an external magnetic field.
![Page 19: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/19.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
In ferromagnetic substances the orientations of magnetic fields from unpaired electrons are affected by spins from electrons around them.
![Page 20: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/20.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Electron Configurations and Oxidation States
When an external field is applied and then removed, the substance maintains the magnetic moment and becomes a permanent magnet.
![Page 21: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/21.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Chromium
• Chromium is oxidized by HCl or H2SO4 to form blue Cr2+ ion.
• Cr2+ is oxidized by O2 in air to form green Cr3+.
• Cr is also found in the +6 state as in CrO4
2− and the strong oxidizer Cr2O7
2−.
![Page 22: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/22.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Iron
• Iron exists in solution in +2 or +3 state.
• Elemental iron reacts with non-oxidizing acids to form Fe2+, which oxidizes in air to Fe3+.
![Page 23: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/23.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Iron
• Brown water running from a faucet is caused by insoluble Fe2O3.
• Fe3+ is soluble in acidic solution, but forms a hydrated oxide as a red-brown gel in basic solution.
![Page 24: Metals and Metallurgy © 2009, Prentice-Hall, Inc. Sections 23.5-23.8 Metals and Metallurgy Chemistry, The Central Science, 11th edition Brown & LeMay.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e835503460f94b84bec/html5/thumbnails/24.jpg)
Metalsand
Metallurgy
© 2009, Prentice-Hall, Inc.
Copper
• In solution copper exists in the +1 or the +2 state.
• +1 salts are generally white and insoluble.
• +2 salts are commonly blue and water-soluble.