Answer:
Cac2 is a answer please mark me brainliest 
 
        
             
        
        
        
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.     
 
        
                    
             
        
        
        
Answer:
4.25*10^18
Explanation:
1 mole =6.023*10^23 particles
so 7.07*10^-6 mole=6.023*10^23*7.07*10^-6 particles=4.25*10^18 particles
 
        
             
        
        
        
Answer:
physical property
Explanation:
it is physical so is any melting and boiling point
 
        
                    
             
        
        
        
The answer you need is B. Pollution. Have in mind that Caves contain carvings and depictions that are formed from acids running through the limestones of the cave. The sulfuric acid that helped form the Lechugilla caves come from pollution.I hope this info can help you