Problem 2
On what basis did Mendeleev construct his periodic table? On what basis are the elements arranged in the modern periodic table?
Problem 3
Using their positions in the periodic table, explain why is it not surprising that strontium-90, a radioactive isotope, replaces calcium in newly formed bones.
Problem 5
Why would you reasonably expect cadmium to be a contaminant in zinc but not in silver?????
Problem 6
Using the symbol for nitrogen, \({ }_{7}^{14} \mathrm{~N}_{2}^{0},\) indicate what information is conveyed by the two superscripts, and what information is conveyed by the two subscripts.
Problem 7
Make a rough sketch of the periodic table and mark off those areas where you would find (a) the representative elements, (b) the transition elements, and (c) the inner transition elements.
Problem 8
Which of the following is (a) an alkali metal? Ca, \(\mathrm{Cu}\), In, \(\mathrm{Li}, \mathrm{S}\) (b) a halogen? Ce, \(\mathrm{Hg}, \mathrm{Si}, \mathrm{O}, \mathrm{I}\) (c) a transition element? \(\mathrm{Pb}, \mathrm{W}, \mathrm{Ca}, \mathrm{Cs}, \mathrm{P}\) (d) a noble gas? \(\mathrm{Xe}, \mathrm{Se}, \mathrm{H}, \mathrm{Sr}, \mathrm{Zr}\) (e) a lanthanide element? \(\mathrm{Th}, \mathrm{Sm}, \mathrm{Ba}, \mathrm{F}, \mathrm{Sb}\) (f) an actinide element? Ho, \(\mathrm{Mn}, \mathrm{Pu},\) At, \(\mathrm{Na}\) (g) an alkaline earth metal? \(\mathrm{Mg}, \mathrm{Fe}, \mathrm{K}, \mathrm{Cl}, \mathrm{Ni}\)
Problem 9
Name five physical properties that we usually observe for metals.
Problem 13
Which physical property of metalloids distinguishes them from metals and nonmetals?
Problem 15
Most periodic tables have a heavy line that looks like a staircase starting from boron down to polonium. What information does this line convey?
Problem 20
What is the difference between an atom and a molecule?
