How many valence electrons do the halogens possess?

Explanation:

        This table summarizes it:

Group number        number of valence electrons

     1                                      1

     2                                     2

    13                                     3

    14                                     4

    15                                     5

    16                                     6

    17                                      7

    18                                      8

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.