The one with higher mass has a higher density because it fits more mass into the same amount of space (volume).
I think the answer is C. An element or compound that cannot be physically separated. Sorry if im wrong.
The correct answer is 42. I know this answer is right because i have already turned my assignment in and got it right.
Answer:
the wavelength of radiation emitted is 
Explanation:
The energy of the Bohr's hydrogen atom can be expressed with the formula:

For n = 7:


For n = 4


The electron goes from the n = 7 to the n = 4, then :


Wavelength of the radiation emitted:

where;
hc = 1242 eV.nm

