Which best describes the motion of helium atoms in gaseous helium

Random motion in all directions.

Explanation:

It must be understood that the movement of atoms in a molecule is strictly based on the kinetic energy possessed by these particles.

Now, the gaseous state gives the highest level of freedom to these particles and thus they possess their highest kinetic energy in this state.

In gaseous helium, the atoms are expected to have a very high kinetic energy and thus they move in a haphazard or in an irregular manner.

This is principally due to the fact that in the gaseous state, atoms are most less confined and thus they are not restricted to a certain space.

This is in sharp contrast to the movement of atoms in the solid and liquid state. While atoms are mostly confined in the solid state such that they only merely vibrate about a fixed point, their movement in the liquid state is less restricted and they exhibit more freedom. This however is far less than the amount of freedom the gaseous state would avail its own particles.

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates