<span>H2C2O4(aq) + 2OH- --> C2O4^2- + 2H2O(l)</span>
Democritus developed the atomic model. He theorized that atoms were specific to the material which they composed. He also believed that the atoms different in size and shape, were in constant motion in a void, collided with each other; and during these collisions, could stick together.
Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
Explanation:
The relation between energy and wavelength is as follows.

This means that energy is inversely proportional to wavelength.
As it is given that energy of a hydrogen atom and a helium atom is same.
Let us assume that
. Hence, relation between their wavelengths will be calculated as follows.
... (1)
... (2)
Equating the equations (1) and (2) as follows.

Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.