A helium balloon displaces the amount of air. The weight of the helium in the balloon + the balloon fabric = lighter than the air that it displaces. Helium is lighter than air, so therefore, if it's in a balloon, the balloon will float.
Answer:
Six
The coordination number of sodium is 6. Likewise, six sodium ions immediately surround each chloride ions, making the coordination number of chloride also equal to 6. Because the formula unit of sodium chloride displays a 1:1 ratio between the ions, the coordination numbers must be the same.
The answer is the atomic mass.
Answer:
1. 2+ (
).
2. 0 (
).
Explanation:
Hello,
In this case, the described chemical reaction is a redox reaction in fact, since the oxidation states of both magnesium and copper change as shown due to the displacement:

Therefore:
1. Since copper is the cation in the copper (II) nitrate, the (II) means that its charge is 2+ (
).
2. Since copper is alone, it means no electrons are being neither shared not given, its charge is 0 (
).
Best regards.