Answer:

Explanation:
In all atoms, the number of protons = number of electrons, as a result the atom is neutral. Losing or gaining electrons will make the atom electrically charged and we call an electrically charged atom an ion.
Ca 2+ would be the symbol because losing two negative electrons makes calcium's nucleus more positive by two protons. 
 
        
                    
             
        
        
        
Answer:
I Think its ABC
Explanation:
No air is the lightest
Helium is lighter than regular air that's why it goes up so then the regular air would be heaviest.
 
        
             
        
        
        
D. 
Have a longer revolution time since they definitely do not get warmer, They do not have fewer moons (Jupiter has about 100 and earth has 1) they are not smaller in diameter (Earth v Jupiter)