1. Discuss briefly the applications of isotopes in nature
2. Classify each of the following changes in matter as physical [PI or chemical[C]
A.Grinding chalk into powder.
B. Burning gasoline.
C. Dissolving salt in water. D.Hammering gold into foil.
E. Dissolving zinc in acid.
F. Tearing a piece of paper. G.Digesting food.
14.Stretching copper into wire.
3. Define the amino acids and give three examples of it with their structure.
4. By using the periodic table below answer this question. Write the symbol and list, by number, both the period and group of each of these elements.
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Symbol
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Period Group
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1. Beryllium
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2. Argon
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3. Lead
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4. Sulfur
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