tailieunhanh - Ebook Materials handbook: Part 2

(BQ) Part 2 book "Materials handbook" has contents: Definitions and reference charts and tables, the structure of matter, waves and colors as material elements, property of flavor in materials, fundamentals of biotic materials, units of measure. | Materials, Their Properties and Uses Downloaded from Digital Engineering Library @ McGraw-Hill () Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Source: Materials Handbook Part 2 Structure and Properties of Materials Downloaded from Digital Engineering Library @ McGraw-Hill () Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Structure and Properties of Materials Downloaded from Digital Engineering Library @ McGraw-Hill () Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Structure and Properties of Materials THE STRUCTURE OF MATTER 1069 The Structure of Matter Elements, or atoms, are the basic building blocks of all tangible materials in the universe. There are 92 natural elements, or material atoms, almost all of which are stable, from hydrogen, atomic number 1, or element 1, to uranium, or element 92. Elements of higher atomic weight than uranium are made, but they are unstable, their time decay being measured progressively as half-life. The atom gets its name from the Greek word atomos, meaning indivisible, and it is not divisible by ordinary chemical means. The elements are used either alone or in combination for making useful products. They combine either as mechanical mixtures or as chemical compounds. In a mixture each element retains its original nature and energy, and the constituents of the mixture can be separated by mechanical means. In chemical compounds of two or more elements, the original elements lose their separate identities; the new substance formed has entirely different properties, and the atomic energy stored within the compound is not equal to the sum of the elemental energies. The atoms in .