Elements and the Periodic Table

Much of the main group metals and non-metals found in vivo are highly solvated by water and produce a pressure within capillaries, arteries, etc. For example, blood plasma approximates to 150 mmol dm 2 sodium chloride. This accounts for a large proportion of the water in humans. Conditions which cause imbalances away from this constant pressure of aquation (called the isotonic pressure) can cause serious cramps in the patient. 

If there were a flag that represented the science of chemistry, it would be the periodic table. The periodic table is a concise organizational chart of the elements. The periodic table not only summarizes important facts about the elements, but it also incorporates a theoretical framework for understanding the relationships between elements. The modern periodic table attests to human s search for order and patterns in nature. As such, the periodic table is a dynamic blueprint for the basic building blocks of our universe. This chapter examines the development of the modern periodic table and presents information on how the modem periodic table is organized. 

The organization of the elements into the first modern periodic table in 1869 depended on two important developments. One was that enough elements had to be identified to organize the elements into a meaningful pattern. Nine elements were known in ancient times. These were gold, silver, iron, mercury, tin, copper, lead, car- 

As the number of elements increased, so did attempts to organize them into meaningful relationships. Johann Dobereiner (1780-1849) discovered in 1829 that certain elements had atomic masses and properties that fell approximately mid-way between the masses and properties of two other elements. Dobereiner termed a set of three elements a triad. Thus, chlorine, bromine, and iodine form a triad Dobereiner proposed several other triads (lithium-sodium-potassium, calcium-strontium-barium). Dobereiner recognized that there was some sort of relationship between elements, but many elements did not fit in any triad group, and even those triads proposed displayed numerous inconsistencies. 

The second development that led to the modern periodic table was the acceptance of specific atomic masses for the elements. While today we readily accept the masses given in a periodic table, there was much 

Despite Meyer s efforts, Mendeleev receives the majority of credit for the modern periodic table. Mendeleev s table resulted from years of work examining the properties of the elements. Mendeleev s method involved writing information about the elements on individual cards and then trying to organize the cards in a logical order. His genius resulted from modifications he introduced into his table that others had not included. He produced his table in 

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Abbgy, Theodore S. Elements and the Periodic Table What Things Are Made Of. Quincy, IL Mark Twain Media, 2001. 

In Part 1, you will use the skills and content you learned in Unit 1, Matter and Chemical Bonding. In particular, you will be applying your knowledge of elements and the periodic table,... 

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