Helium, He is the most lightest among the given four elements. As the molecular mass of helium,He is about 4.002602 u. It is considered the second most lightest element inside the periodic table after the hydrogen,H atom which is the lightest of all.
Explanation:
<u>Velocity dependence upon the molecular weight of the element:</u>
The molecular weight of the different elements gives them the very specific features including the ability to travel fast in a given space. While the helium,He is considered one of the lightest elements in the universe so, it has a greater velocity among the four options.
<u>For example:</u>
A person with less weight will run much faster as compared to a person having more weight.
The correct option is C. Helium gas will have the highest velocity at a given temperature because it has the lowest atomic mass of all the gases given. The atomic mass of gases affect their rate of movement. The lower the atomic mass, the faster the gas molecules moves and the higher the atomic mass, the slower the gas molecules move.
Group 1A(1), the alkali metals, includes lithium, sodium, and potassium. Group 7A(17) the halogens, includes chlorine, bromine, and iodine. hope this helps:)
