Answer:
6.022 x 10^23 particles
Explanation:
Chemists have chosen to count atoms and molecules using a unit called the mole (mol), from the Latin moles, meaning “pile” or “heap.”
One mole is 6.022 x 10^23 of the microscopic particles which make up the substance in question.
Hope this helped! :^)
Answer: difference in Vander Waals forces
Explanation:
The intermolecular force of attraction between the molecules in chlorine is WEAKER than that of Bromine.
This force is known as VANDER WAALS forces. And it DECREASES down the group; so Chlorine which is placed higher is a GAS, while Bromine placed lower in Group 7 is a LIQUID.