7 would be correct because I divide it
Answer:
Explanation:
Calcium is all around us. The average human contains approximately 1kg of calcium, of which 99% is stored in our bones. It is the 5th most abundant element in the earth's crust, occurring widely as calcium carbonate which is more commonly known as limestone. It is also the fifth most abundant dissolved ion in seawater.
3H + 3Br = HBr9 Organic chemistry mechanism
The third option because the elements mentioned in that selection are in the same group, they must have similar properties.