The mass numbers for two isotopes are unequal because they have different numbers of NEUTRONS.
        
                    
             
        
        
        
Answer:
1. Rutherford did the scattering experiment and observed that some of the rays bounce back. He concluded that there is a mass in which positive charge is concentrated. This marks the discovery of nucleus.
2. J.J Thomson discovered electrons by conducting cathode ray experiment.
3. Dalton postulated that matter is made up of small particles caled atoms
 
        
             
        
        
        
The ribosomes are the ones delivering the products of the endoplasmic reticulum
        
             
        
        
        
M=mol/liter
We know that we have 150ml=.15 L and .1 mol of HCl
Rearranging the molarity equation, we get
mol=M*l
mol=(.15)(.1)
=.015 mol
        
                    
             
        
        
        
Answer:
The core of Jupiter and Saturn is made up of rock,metal and hydrogen compounds, while the core of Uranus and Neptune is made up of rock,metals,water, methane, and ammonia.
Explanation:
The Jovian planets include, Jupiter, Saturn, Uranus, and Neptune. These planets when compared to terrestrial planets are small, with dense cores and surrounded by layers of gas.