Answer:
146 
Explanation:
 uranium is 92 and the mass number of the isotope is given as a 238 therefore it is not the two protons 92 electrons and 
real explanation Google it
 
        
             
        
        
        
Answer: 5.747 * 10^14 Hz
Explanation: 
Convert 522nm to m = 522 * 10^-9 m (since 1nm=10^-9m)
If c = wavelength * frequency, where c is the speed of light (3.0 * 10^8 m/s), then you can manipulate the equation to solve for frequency (f).
f = c / wavelength
Plug in the given numbers:
f = (3.0 * 10^8) / (10^-9)
f = 5.747 * 10^14 Hz
 
        
                    
             
        
        
        
The answer is C Becuz D is a compound and that is the only answer that says it
 
        
             
        
        
        
Answer:
C. Scientists accepted the model at first but later rejected it.  
Explanation:
Scientists accepted the model at first because it explained the hydrogen emission spectrum.
However, with the development of quantum mechanics, scientists had to modify the model (not reject it).
Electrons still had specific energies, but they no longer travelled in fixed orbits.
Instead, electrons had a probability of being found in a given region of space.
 
        
                    
             
        
        
        
Non of these bc it makes the most likely