Answer:
there are two significant figures is the number 8400
Explanation:
Because it has atomic no. = 1 (according to modern periidic table)
All the following are equal to Avogadro's number EXCEPT a. the number of atoms of bromine in 1 mol Br₂.
1 mol Br₂ contains Avogadro’s number of molecules of Br₂.
However, each molecule contains two atoms of Br, so there are
<em>2 × Avogadro’s number of Br atoms </em>in 1 mol Br₂.
I think its 2-, it gained 2 electrons.
