1. What time is it now? 2. When do your classes usually begin? 3. When
did the lecture begin? 4 . 1 believe my watch is fast, what time is it by your
watch? 5. At what time shall we meet? 6. At what time are your classes
over? 7. When do you get up? 8. When will you be free? 9. When will you
come to the laboratory?
Ex. 3. Make up sentences or short stories with the following words:
1) introduce, they, symbols, Swedish, begin, shorthand, chemist, simple,
Berzelius, element, name; 2) phenomenon, allotropy, such, be, when, can,
form, element, exist, different, the same, state, physical; 3) act, formula,
law, the very, write, assume, composition, constant; 4) gram, weight,
molecular, be, element, seem, atomic
Ex. 4. Give detailed answers to the following questions:
1. In what way were the modem symbols for the elements introduced?
2. What is the meaning of a chemical symbol for an element? 3. In what
way do we usually write formulae for compounds? 4. What law is the
basis for writing the formula of a compound? 5. What is an atom? 6. What
is a molecule?
Ex. 5. Discuss the following topics:
1. The History of the Introduction of Symbols.
2. Symbols for Representing Elements.
3. Symbols for Representing Compounds.
DO YOU KNOW THAT...
Berzelius published his first paper on the new nomenclature in 1813.
A year later, he published his second article in which he formulated the
rales for writing formulae. The number of atoms was marked by a figure at
the upper end of the symbol. If a compound contained two atoms of a
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