Answer: Be= 2, C =4,  Li = 1 and  B=3
Explanation:
The valence shell can be define as the outermost shell of an atom that contains the valence electrons.
Beryllium (Be), electronic configuration; 1s2 2s2, = 2 electrons in its valence shell. 
Carbon (C), electronic configuration; 1s2 2s2 2p2, = 4 electrons in its valence shell.
Lithium (Li), electronic configuration; 1s2 2s1 = 1 electron in its valence shell.
Boron (B) , electronic configuration; 1s2 2s2 2p1 = 3 electron in its valence shell.
 
        
             
        
        
        
Answer:
17.04 g/mol
Explanation:
Molar Mass of NH₃
we know that 
Nitrogen has 14.01 gram/mol
And Hydrogen has 1.01 gram/mol
but we have 3 Hydrogens So we multiply 
1.01 by 3 i.e., 3.03
Now, add
 14.01
+<u> </u><u>3</u><u>.</u><u>0</u><u>3</u>
 17.04
So, The molar mass of ammonia, NH₃ is
17.04 g/mol
<u>-TheUnknown</u><u>Scientist</u>
 
        
             
        
        
        
Approximately 119.4 g, you take the mass on the periodic table of each element and add the numbers up
        
             
        
        
        
In the lake that the rivers lead, water molecules evaporate into the sky and form clouds. In the sky, these water droplets condense and form clouds that will eventually rain.