That statement is true
it was easy to organize 'all' the elements in a group of threes because back then they only knew about 15 - 20 elements
hope this helps
O.N. of Na = +1
O.N. of O = -2
Let, O.N. of Tin = x
1*2 + x + -2*2 = 0
2+x-4 = 0
x-2 = 0
x = 2
SO OPTION C IS YOUR ANSWER......
Lies just beyond the continental slope is the open ocean zone and it has three subzones namely the epipelagic(sunlit zone), mesopelagic(disphotic zone) and bathypelagic zones(aphotic zone). The oceanic zone covers 65% of the ocean's water and where different types of terrains can be found. From deep trenches, deep sea volcanoes and basins. A variety of sea creatures can also be found on each subzone.
1. Convert gallons to mL. 1 gal = 3785.4117840007 mL, multiply that by 29 and get 109776.94173602 mL.
2. Since there is one gram per every mL, there are 109776.94173602 g of water in the fish tank.
3. Convert g to pounds. 1 g = 0.0022 pounds. Multiply 109776.94173602 by 0.0022 and end up with about 241.5 pounds of water.