HW #1 Soln

HW #1 Soln - Homework #1 Answers Chapter 1: 1.1 Define (or...

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Homework #1 Answers Chapter 1: 1.1 Define (or explain) what is meant by a property of a material? Name the 6 basic materials properties. A material’s property is the response to a stimuli. The basic classifications of material properties are: Mechanical, Electrical, Optical, Magnetic, Thermal and Chemical Reactivity (Deteriorative). 1.2 What are the three basic categories of materials? Metals, ceramics, plastics Homework Chapter 2: 2.0 Materials can be classified as heterogeneous or homogeneous, solutions and pure, elements or compounds. List all that apply to the following (1, 2 or 3 of the classifications may apply): (a) Concrete (b) Deionized Water (c) Helium (d) 18K Rose Gold (75% Au-25%Cu) (a) Concrete: heterogeneous (b) Dionized Water: homogeneous, pure, compound (c)Helium: homogeneous, pure, compound (d) 18K Rose Gold: homogeneous, solution. 2.1 What is the difference between atomic number, atomic mass and atomic weight? Atomic number is the number of protons in an atom; it defines the element. Atomic mass is the mass of an individual atom and depends on both the element and the isotope. Atomic weight is the abundance weighted average of the atomic masses of an atom's naturally occurring isotopes. 2.7 Give the electron configurations for the following ions: Fe 2+ , Al 3+ , Cu + , Ba 2+ , Br - , and O 2- . Table 2.2 will be a big help. Fe 2+ : The electron configuration for a neutral iron atom is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 . In order to become a 2 + ion it must lose two electrons—in this case the two 4s electrons. Thus, the electron configuration for an Fe 2+ ion would be 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4 . However, filled and half-filled d- orbitals are energetically favorable to the point that one of the 4s electrons moves to the 3d
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HW #1 Soln - Homework #1 Answers Chapter 1: 1.1 Define (or...

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