Periodic table is confusing ;-; plz helppp Okay so the group number is supposed to equal to the valence electrons of the elements in said group. But, for example fluorine, has 7 valence electrons even though it's in group 17. I know it's unlikely for a non-metal to have 17 valence electrons, but still I'm quite confused??? Is there some special way to read groups I missed??

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.