I am assuming you are talking about Neon. The rate of diffusion is directly proportional to the molar mass of the gas. Since neon has a molar mass of 20.18 grams, the gas must have a lower molar mass and must be a gas at 273 Kelvin. There are several elements that fulfill this criteria: Hydrogen, Helium, Oxygen, Nitrogen, and Fluorine.
We have to complete all the given reactions.
1. Fe(s) + CuCl₂ → Cu + FeCl₂
2. Cu(s) + FeCl₂(aq) → NR (no reaction takes place)
3. K(s) + NiBr2(aq) → NR (no reaction takes place)
4. Ni(s) + KBr(aq) → K + NiBr₂
5. Zn(s) + Ca(NO₃)₂(aq) → NR (no reaction)
6. Ca(s) + Zn(NO₃)₂(aq) → Zn(s) + Ca(NO₃)₂(aq)
Explanation:
Atomic number is defined as the number of an element which represents total number of protons.
When an atom is neutral then it means it contains same number of protons and electrons.
On the other hand, atomic mass is defined as the sum of total number of protons and neutrons present in an atom.
Protons of every element remains fixed because it shows the identity of each element but if we change the number of neutrons then also identity of the atom will remain fixed. This is because changing the number of neutrons will not show any change in number of protons.
For example, 
and 
are isotopes of hydrogen and they have same number of protons but different number of neutrons.
Thus, we can conclude that number of neutrons can vary without changing the identity of the element.
Answer:
Diffusion in gases
Diffusion is driven by differences in concentration. When chemical substances such as perfume are let loose in a room, their particles mix with the particles of air. The particles of smelly gas are free to move quickly in all directions
Explanation:
hope this helps
