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Elements. Pgs 54-57. What is an element?. A pure substance than cannot be separated in to simpler substances by physical or chemical means. An Element Has O nly O ne T ype of Particle. A pure substance is one in which there is only one type of particle. Elements are pure substances.
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Elements Pgs 54-57
What is an element? • A pure substance than cannot be separated in to simpler substances by physical or chemical means.
An Element Has Only One Type of Particle • A pure substance is one in which there is only one type of particle. • Elements are pure substances. • Atoms of pure substances are alike no matter where they are found.
Every Element Has Unique Properties • Characteristic properties of an element help you identify the element no matter what amount you have of it. • Boiling point • melting point • density
Identifying Elements by Their properties • If we look at cobalt, iron, and nickel we can see different characteristic properties for them. • Cobalt • Melting point 1,495 C • Density 8.9g/mL • Conducts electric current • Unreactive to oxygen
Iron • Melting point 1,535 C • Density – 7.9g/mL • Conducts electric current • Reacts with oxygen to form rust • Nickel • Melting point 1,455 C • Density 8.9g/mL • Conducts electric current • Unreactive to oxygen
Elements are Grouped into Categories • Elements are grouped according to their shared properties. • Iron, nickel and cobalt all are shiny, conduct electricity and thermal energy. • They belong to the group called metals
Metals • Metals are: • Shiny • Good conductors of thermal and electric energy • Malleable • Ductile
Nonmetals • Nonmetals are : • Dull • Poor conductors of thermal and electric energy • Tend to be brittle • Nonmalleable • Ex. Neon, carbon, sulfur, bromine
Metalloids • Metalloids (semiconductors) are similar to both metals and nonmetals. • Some are shiny or dull • Some are malleable or ductile and others are not. • Some conduct electricity or thermal energy. • Ex. Silicon, antimony, boron
If you know the category you know the properties • Just like finding a movie in the action section or comedy section, you can tell what type of element it is based on its properties. • If it shares properties with metals, it is a metal. • If it shares properties with nonmetals it is a nonmetal • If it shares properties with both, it is a metalloid.