It’s c had this problem last week
Negatively charged particles in atom - Electrons
The answer would be 5.5g because you have to subtract 8.2 minus 2.7 and you get 5.5g so basically the answer is C.
I believe it is “Conduction” im not 100% sure tho, I haven’t done this since the 7th grade.
the density increases down the group.
