Elements and Compounds

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What is an element?

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An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include hydrogen, oxygen, and gold.

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What is a compound?

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A compound is a substance formed when two or more elements chemically bond together. Examples include water (H2O) and carbon dioxide (CO2).

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How are elements represented in chemistry?

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Elements are represented by chemical symbols, which are usually one or two letters. For example, H for hydrogen and O for oxygen.

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What is the difference between an element and a compound?

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An element is a single type of atom, while a compound consists of two or more different types of atoms bonded together.

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What is a chemical formula?

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A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound. For example, H2O indicates two hydrogen atoms and one oxygen atom.

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What is a mixture?

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A mixture is a combination of two or more substances that are not chemically bonded. Examples include air and salad.

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What is the periodic table?

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The periodic table is a tabular arrangement of elements, organized by increasing atomic number, which shows the relationships between them.

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What are metals?

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Metals are elements that are typically shiny, good conductors of heat and electricity, and malleable. Examples include iron, copper, and aluminum.

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What are nonmetals?

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Nonmetals are elements that lack the characteristics of metals. They are usually poor conductors of heat and electricity. Examples include sulfur and nitrogen.

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What are metalloids?

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Metalloids are elements that have properties of both metals and nonmetals. Examples include silicon and boron.