Answer is: the discovery of sub atomic particles like electrons.
J. J. Thomson discovered the electron in 1897.
His "plum pudding" model (1904) suggested: the electrons are embedded in the positive charge.
With this model, he abandoned his earlier hypothesis (the atom was composed of immaterial vortices).
J.J. Thomson placed two oppositely charged electric plates around the cathode ray. He did experiments using different metals as electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.
Tomson concluded that atoms are divisible and that the corpuscles are their building blocks (atoms are made up of smaller particles).
Answer:
₈₆²²²Rn → ₈₄Po²¹⁸ + H₂⁴
Explanation:
The given nuclear reaction shows alpha decay.
₈₆²²²Rn → ₈₄Po²¹⁸ + H₂⁴
Properties of alpha radiations:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number less than 2 as compared to parent atom the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy
Answer: 7.79 grams of ethanol were put into the beaker.
Explanation:
To calculate the mass of ethanol, we use the equation:
Density of ethanol = 0.779 g/mL
Volume of water = 10.00 mL
Putting values in above equation, we get:
Thus 7.79 grams of ethanol were put into the beaker.
The equation is: C+O2=>CO2
Since we got 10 molecules of CO2 new balanced equation would be 10C+10O2=>10CO2
from this equation we can see that we have 10 molecules of oxygen, however ,we need to find atoms. There are 2 atoms in the oxygen molecule so we need to multiply 10 by 2 which gives us 20 atoms.
The answer: there are 20 atoms of oxygen
