The correct answer to
the question that is stated above is letter  c, <span> the outer electron shell.</span>
Valence electrons occur<span> in the outermost shells of an </span>atom.
>> <span>Valence electrons are </span>electrons<span> that are associated with an </span>atom<span>, and that can participate in the formation of a </span>chemical bond.
        
                    
             
        
        
        
Answer:
A
Explanation:
The option A is draw well about sha
 
        
             
        
        
        
Answer:
the reactivity and the valence electrons 
Explanation:
the reactivity of the elements would have played a significant role in why such elements were grouped together. the number of valence electrons dictates how reactive an element is - the less valence electrons the more reactive it is. the column, group 1 in which these elements are put together in, show that each of the elements have 1 valence electrons and are therefore reactive. 
you can go on to further explain what valence electrons are, explain what the group numbers are associated with the valence electrons and how valence electrons effect reactivity. further this, talk about how the three elements have the same number of valence electrons and therefore were grouped together 
 
        
             
        
        
        
An isotope of nitrogen containing 7 neutrons would be nitrogen-7
        
             
        
        
        
The awnser would be (C.) As it is the only correct one.