Answer:
1.)
2.) 
3.) 2HCl
4.) MgO
5.) Mg and 
6.) 
and
7.)Na and 
8.) 3 aluminums and 3 chlorides
Explanation:
The atoms C,H,O and N becomes more electronegative as the periodic table's right side and top get increasingly electronegative as you move down it. A hydrogen bond needs to share elements with hydrogen in order to exist.
As you move up and to the right of the periodic table, the electronegative properties increase. To form a hydrogen bond, elements would have to be shared with hydrogen. Each element becomes increasingly electronegative as you move further right on the periodic table, with the exception of noble gases (which aren't particularly reactive).
In order to obtain stability, atoms C, H, O, and N would therefore most likely desire to share their electrons (i.e., they are more electronegative because they wish to "hog" electrons). Due to its intermediate electronegativity, hydrogen has a mid-range potential for forming bonds with other molecules.
Learn more about hydrogen element here:
brainly.com/question/16979348
#SPJ4
