Complete these structures by adding electron dots as needed.

This is hard to show but here is how you would determine these. NOTE each dot is an electron. 
Question 1) 
F-H 
1) determine the valance electrons for each. F has 7 and H has 1 
2) one electron from both F and H form the bond "-" which means that you still have 6 electrons to place around F and none to place around H. Place the 6 in sets of 2 around the F 
.. 
F-H 
¨ 
Question 2) 

2) H-O-H 
H has 1 valence electron minus 1 used in the bond to O = 0 electrons to place 
H has 1 valence electron minus 1 used in the bond to O = 0 electrons to place 
O has 6 valence electrons minus 2 used in the bonds to the H's = 4 electrons to place 

H-O-H: place two dots above and below the oxygen 

Question 3) 
3) O=NH : NOTE: a double bond requires O and N to share two of their electrons each 
O has 6 valence electrons minus 2 used in the bonds to N = 4 electrons to place 
N has 5 valence electrons minus 3 used in the bonds to O and H = 2 electrons to place 
H has 1 valence electron minus 1 used in the bond to N = 0 electrons to place 
place the 2 dots on top and bottom of oxygen. 
place 2 above the N