http://www.ck12.org Chapter 6. The Periodic Table
- In the modern periodic table, elements are arranged into periods and groups. Elements in the same group have
similar properties. - Elements can be classified as metals, nonmetals, or metalloids.
Lesson Review Questions
Reviewing Concepts
- Compare Dobereiner’s triads to the modern periodic table. What aspects of his idea agreed with the modern
table and what aspects did not? - Why did Mendeleev leave empty spaces in his periodic table?
- Explain the significance of the discovery of gallium to Mendeleev’s periodic table.
- What discovery occurred after Mendeleev’s periodic table was published that allowed Moseley to improve it?
- Identify each physical property as more characteristic of a metal or of a nonmetal.
a. luster
b. malleability
c. brittle texture
d. low melting point
e. good conductor of electric current
Problems
- Use theFigure6.1 to answer the following.
a. How many elements were known by 1700?
b. How many elements were discovered between 1735 and 1843? - The atomic mass of beryllium (Be) is 9.01 amu. The atomic mass of calcium (Ca), which is in the same group
as beryllium, is 40.08 amu. Based only on this information, what would you predict to be the atomic mass of
magnesium (Mg), which is also in the same group but is between Be and Ca? - Use the periodic table to put the following elements into pairs that would be expected to have similar chemical
properties: Ba, S, Br, Ca, K, F, Se, Na - Identify each element below as a metal, nonmetal, or metalloid.
a. phosphorus
b. boron
c. cesium
d. xenon
e. bismuth - Write the name and symbol of the element located at each of the following positions on the periodic table.
a. period 2 and group 16
b. period 5 and group 9
c. period 4 and group 5A
d. period 6 and group 12
Further Reading / Supplemental Links
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