Here we have to compare the Bohr atomic model with electron cloud model.
In the Bohr's atomic model the electrons of an element is assumed to be particle in nature. Which was unable to explain the deBroglie' hypothesis or the uncertainty principle and has certain demerits.
The uncertainty principle reveals the wave nature of the electrons or electron clod model. The Bohr condition of a stable orbits of the electron can nicely be explained by the electron cloud model, the mathematical form of which is λ = nh/mv, where, λ = wavelength, n is the integral number, h = Planck's constant, m = mass of the electron and v = velocity of the electron.
The integral number i.e. n is similar to the mathematical form of Bohr's atomic model, which is mvr = nh/2π. (r = radius of the orbit).
Thus, the electron cloud model is an extension of the Bohr atomic model, which can explain the demerits of the Bohr model. Later it is revealed that the electron have both particle and wave nature. Which is only can explain all the features of the electrons around a nucleus of an element.
Hydrazine is a mixed chemical...look up what is in Hydrazine. Then find the chemicals in it. 13.00g of hydrazine can react to anything....water, gas, etc. but it might not be visible.
The type of chemical reaction that the reactants will undergo would be a single displacement reaction.
In a single displacement reaction, one element gets substituted or replaced by another element in a compound. This often leads to the formation of a new compound (aqueous) and a new element (solid or precipitate).
Thus, the complete equation of the reaction becomes:

Cu displaced Ag from AgNO3. Thus Ag becomes precipitated in solution while a new compound, CU(NO3)2 is formed.
More on displacement reactions can be found here: brainly.com/question/13219117
Answer:
D
Explanation:
Mendeleev periodic table predicted the properties of undiscovered element like the eka-aluminium.