Choices 'a', 'c', and 'd' are true.
In choice 'b', I'm not sure what it means when it says that masses
are 'balanced'. To me, masses are only balanced when they're on
a see-saw, or on opposite ends of a rope that goes over a pulley.
Maybe the statement means that the mass of the nucleus and the
mass of the electron cloud are equal. This is way false. It takes
more than 1,800 electrons to make the mass of ONE proton or
neutron, and the most complex atom in nature only has 92 electrons
in it. So there's no way that the masses of the nucleus and the electrons
in one atom could ever be anywhere near equal.
<span>When an electron is hit by a photon of lights,it absorbs the quanta of energy the photon was carrying and moves to a higher energy state.Electrons therefore have to jump around within the atom as they either gain or lose energy.</span>
The particles in a liquid are extremely fast, not faster than a gas, but faster than a solid. The way the particles move allow you to get volume but not area for it doesn't have a defiant shape
If you'r referring to some objects, it means that the mass of the object is less than the water so it floats. If the mass of an object is greater than the mass of the water, it will sink. Compare it to a balloon, helium makes it rise, while normal air makes it sink.
If you did this then it could lead to cheating or someone else getting hurt.