Answer:
the properties of three undiscovered elements is the correct answer.
Explanation:
After he completed his work Mendeleev predicted the properties of the undiscovered elements.
In the year 1871, Dmitri Mendeleev predicted the detailed existence and the properties of the three elements that are undiscovered and he gained tremendous fame.
He left the gap in the table to put the elements which are not identified at that time and by glancing at the physical and chemical properties of an element next to the gap, Mendeleev could predict the properties of the not discovered elements.
Fission reactions generate thermal energy
The Milky Way is a SBc barred spiral galaxy.
The answer is A. this process is only in the research phase
The process of fusion involves merging of atomic nuclei to
form heavier nuclei resulting in the release of enormous amounts of energy.
Fusion takes place when two low mass isotopes, typically isotopes of hydrogen,
unite under conditions of extreme pressure and temperature. Scientists continue
to work on controlling nuclear fusion in an effort to make a fusion reactor to
produce electricity. However, progress is slow due to challenges with
understanding how to control the reaction in a contained space.
