Answer:
The speed of an electron is 0.01908 m/s.
Explanation:
De-Broglie wavelength is given by:
where, 
= wavelength of a particle
h = Planck's constant = 
m = mass of particle
v = velocity of the particle
Velocity of an electron = v
Mass of an electron = 
Wavelength of electron is twice the displacement in seconds which is velocity of an electron.
Then.wavelength of an electron = 
v = 0.01908 m/s
The speed of an electron is 0.01908 m/s.
In a chemical change, the atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants. When a new substance is formed, the change is called a chemical change. A chemical reaction is a mechanism that takes place when two or more molecules interact to produce new products. A reaction between two atoms or ions or molecules may take place and a new bond is formed and no atom is destroyed or created, but reactants form a new substance.
True ^_^
People had asked this many times and that is why they came up with methods and standards that will answer these type of questions. You can look it up in the NIST or the National Institute for Standards and Technology.
Thomson suggested the model of atom which was a sphere of positive matter within which electronic forces determined the positioning of the corpuscles. The corpuscles were distributed in a uniform sea of positive charge. This was so-called "plum pudding" model.
Answer: C ) Thomson
