The elements whose electron configurations end with f electrons are in the Lanthanide and Actinide series: those long series at the bottom of the Periodic Table (see image).
The atoms are adding electrons into f orbitals, but the f electrons are not always the last electrons in the electron configuration.
For example, the electron configuration of Eu is [Xe]6s²4f⁷, but that of Gd
is [Xe] 6s²4f⁷5d.
I have blocked off in <em>red</em> all the <em>exceptions</em> like Gd.
I believe it is A because a physical change is something that can be changed back to where a chemical change can not be such as burning something.
You need to do something like that your self so sorry can help.
I would imagine they’d be equal.
F = ma
We can treat mass and force as constants because they do not change throughout both systems and they are the same on both systems. That would mean the acceleration would be the same for both systems.
An explanation of this could be the two forces are acting in different directions, so one is positively accelerating the object and the other is negatively accelerating it