Man's physical universe

xanabras

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;

560 MAN IS MASTKRING HIS MATERIAL WORLD

No thought of beauty or convenience in use was shown in naming

such elements as dysprosium, molybdenum, neodymium, manganese,

praseodymium, ytterbium, xenon, and yttrium.

A great many of the elements have names derived from the Greek —

for example, hydrogen (water-producing) ;

chlorine (yellowish-green)

helium (sun); neon (new).

Some elements are named after the particular localities in which

they were discovered or occur — for example, strontium, from Strontian

in Scotland.

The Use of Symbols and Formulas Saves Time.

A symbol is the representation of an element; thus H is a symbol for

hydrogen, and O is a symbol for oxygen. Many of the elements are

known by symbols derived from their former (usually Latin) names.

For example, the symbol for sodium is Na (from Natrium), and the

symbol for mercury is Hg (from Hydrargyrum)

Inasmuch as compounds are composed of elements, the representation

of a compound, called 3. formula, is composed of the symbols of the

elements in the compound. The formula of copper oxide is CuO because

it is composed of copper and oxygen.

1. Define element and compound.

STUDY QUESTIONS

2. What are the three types of elements?

3. How many elements are there?

4. How were the elements named?

5. What was the main idea of the alchemists?

6. Differentiate between mixtures, compounds, and elements.

7. How does a substance differ from a mixture? What are the two types of

substances?

8. Give an outline for the classification of matter.

9. Differentiate between chemical and physical changes.

10. What is analysis?

11. Name the four most abundant elements on the earth's surface.

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