Answer:
Bro I got notification of this question but soory I don't know the answer Hope you understand me
Answer: It is Mole.
Explanation:
Mole is the SI unit of measurement used to measure the number of things, usually atoms or molecules. One mole of something is equal to 6.02214078×1023 of same things (Avogadro's number).
Mass number of an element write in bottom of it!
So, there 80 would be the mass number of ₈₀Br.
Hope this helps!
Answer:
D. all of these are chemical changes
The chemical equilibrium will be unaffected