Chalcogens or oxygen grouo
Elements in groups 16 has six valence electrons.
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C) or group 16
a) alkali metals
The element described above definitely belonged to the alkali metals, the first group on the periodic table. They show the properties indicated in the text.They are metals because only metals are lustrous and malleable. This eliminates the possibility of them being halogens and noble gases. Only group 1 metals reacts vigorously with water to form alkali. Alkali are aqueous solutions that are basic in nature. The reactivity of group 1 metals is due to their one extra electrons in the outer most shell. These electrons are easily and readily lost in order for such atoms to gain stability and replicate the nearest noble gases. The most reactive metal belongs to this group elements. This is why it is nearly impossible to find them occurring alone in free state. Some of the elements in this group are Li, Na, K, Rb, Cs and Fr. Transition metals have variable oxidation states and some can be found alone in nature.
If there are six valence electrons available for bonding it means there must be two electrons in s sub shell and four in p subshell. Thus the element cannot be s block element and it cannot be d or f block element as well. The element must belong to p block.
The first group of p block contains one electron in outermost p subshell.
The first group is 13th group of periodic table.
so in this way the element with four electrons in valence p block will belong to 16th group.