Using the periodic tables, identify the heaviest member of each of the following groups:
(a) alkali metals
(b) chalcogens
(c) noble gases
(d) alkaline earth metals

(a) Alkali metals: Francium (Fr)

(b) Chalcogens: Polonium (Po)

(c) Noble gases: Radon (Rn)

(d) Alkaline earth metals: Radium (Ra)

Explanation:

In the periodic table, the atomic mass increases down the group. Therefore, the last element of a group is the heaviest element of the group.

(a) alkali metals: The chemical elements that are present in group 1 of the periodic table, except hydrogen.

The heaviest member of this group is francium (Fr)

(b) chalcogens: The chemical elements that are present in group 16 of the periodic table

The heaviest member of this group is polonium (Po)

(c) noble gases:  The chemical elements that are present in group 18 of the periodic table

The heaviest member of this group is radon (Rn)

(d) alkaline earth metals: The chemical elements that are present in group 2 of the periodic table.

The heaviest member of this group is radium (Ra)

i think 4.44 moles

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)