I guess you are asking what world should go at the beginning of the sentence. If I am right, it is energy.
Answer:5
Explanation:The pnictogen group, or nitrogen group, is located in column 15 of the periodic table. This family consists of the elements nitrogen, phosphorus, arsenic, antimony, bismuth, and ununpentium (N, P, As, Sb, Bi, and Uup, respectively). Each member of this family contains five valence electrons.
Answer:
Because two minerals can share property's so you need more then one to tell them apart. Hope this helped! :)
Explanation:
Sunlight breaks apart an oxygen molecule to form separate oxygen atoms <span />
1st level = s
<span>2nd level = s,p </span>
<span>3rd level = s,p,d </span>
<span>4th level = s,p,d,f</span>