An oceanic depth-sounding vessel surveys the ocean bottom with ultrasonic waves that travel 1530 m/s in sea-water. The time delay of the echo to the ocean floor and back is 5.55 s .

Ithink it’s 98 because jajajjajansmsmjs

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.