Refer to the periodic table and select the symbol of the element that fits each of the following descriptions:
a) the group IVA/14 semimetal in the fourth period.
b) the third-period alkali metal.
c) the halogen that is normally a solid and not radioactive.
d) the halogen that exists as a reddish-brown liquid at normal conditions.
e) the fourth-period representative element with properties similar to O.