With the principle quantum number being 2, the maximum number that can share this is 8. You can use the general formula 2n^2 to calculate this number (n=quantum level), or you can use the concept of quantum numbers (n, l, m, s) to justify this answer.
        
             
        
        
        
Answer:
Explanation:
The symbol of beryllium is Be. It is located in the second group on the periodic table. 
Beryllium is a divalent cation with a charge of +2.
It is capable of losing 2 electrons in order to be like the noble gas He and this is a more stable configuration. 
 
        
                    
             
        
        
        
<span>According to Mendeleyev-Klapeyron’s equation
pV = nRT,
where p = 160 atm V = 12 R -constant 0.0821 & T = 298 in Kelvin
Using given data, we can determine the amount of Helium gas:
n = pV/RT = (160â™12)/(0,0821â™298) = 78,48 (mol)
For atmospheric pressure (1 atm) and the same amount we can calculate the volume of tank, using previous equation:
V = nRT/p = (78,48â™0,0821â™298)/1 = 1920 (liters)
V = 1920 liters
Thus Answer is 1920 liters</span>
        
             
        
        
        
It becomes an ion.
Orginally, the number of electrons of an atom should be same as the number of protons, and the atom should be electrically neutral, as each proton brings a positive charge and each electron brings a negative charge. However, when an atom loses or gains electrons, the charge would be positive or negative, depending on what the change is. In this way, the atom is no longer an atom, but an ion.
The number of electrons gained or lose by an atom depends on their group number in the periodic table. They'll gain or loose the least electrons in order to have an octet of electrons (or duplet). Which means, their outermost shell electrons would be 8, or 2 for the first shell.
One exam is fluorine. It is in the group VII, it has an outer most shell electron of 7. In order to make fluoride ion, one electron is gained, so that the outer most shell will have 8 electrons. Therefore, fluoride ion has a negative charge, as one electron brings a negative charge.