The elements on the periodic table are listed in increasing atomic number. 
Hydrogen is the first element, and has an A.N. of 1. Also, its very interesting how it doesn't need 8 valence electrons to be stable. 
The second element is Helium, which has an A.N (atomic number) of two. 
        
                    
             
        
        
        
Answer:
C
Explanation:
 
Mitochondria provides energy (ATP) for cells to use 
Nucleus provides genetic code (DNA) 
Ribosomes assemble amino acids chains based on the DNA from nucleus to form proteins
 
        
             
        
        
        
It is translational motion. i know because i found it on this site. its verified too, have a nice day
        
                    
             
        
        
        
 194.5 g of BCl₃ is present in 1 × 10²⁴ molecules of BCl₃.
Explanation:
In order to convert the given number of molecules of BCl₃ to grams, first we have to convert the molecules to moles.
It is known that 1 moles of any element has 6.022×10²³ molecules.
Then 1 molecule will have  moles.
 moles.
So 
Thus, 1.66 moles are included in BCl₃.
Then in order to convert it from moles to grams, we have to multiply it with the molecular mass of the compound.
As it is known as 1 mole contains molecular mass of the compound.
As the molecular mass of BCl₃ will be

Mass of boron is 10.811 g and the mass of chlorine is 35.453 g.
Molar mass of BCl₃ = 10.811+(3×35.453)=117.17 g.


So, 194.5 g of BCl₃ is present in 1 × 10²⁴ molecules of BCl₃.