Lewis Dot Structures

Question 1

Drawing Structures Pt. 1

Answer 1

Choose the central atom(s).
Almost always the least electronegative atom is the central atom.
For example, in ClO2, the Cl is the central atom; in SF5 the S is the central atom.
Occasionally, you will need to choose the unique atom, even when it is the most electronegative: e.g., the O in Cl2O.
A wrong choice usually will be signaled by your being unable to write a valid structure.
Arrange the other atoms around the central atom, in accord with the normal valences of the atoms. That is, do not place more atoms around a central one than it normally can bond to.

Question 2

Drawing Structures Pt. 2

Answer 2

For first and second row elements, the maximum valence = the Group number through Group IV; after that, it is 8 - (the Group number).
The difference is that up through IV, the atoms tend to donate electrons to get an octet, whereas beyond IV, they accept electrons.
Recognition of exceptions will come with experience.
You may find that you will have to place fewer atoms than normal around a central one; this is taken care of later.
Hydrogen never is the central atom. It forms only one bond, so it must generally be in the outer layer of atoms. Therefore, place hydrogen atoms last.

Question 3

Drawing Structures Pt. 3

Answer 3

Place any remaining electrons on peripheral atoms as unshared pairs, starting with the most electronegative such atom.
Fill this atom up to an octet.
Then proceed to the next most electronegative, and so on.
Remember that hydrogens can only have two electrons, and so cannot have any unshared pairs.
If electrons still remain unused, place them on the central atoms as unshared pairs, again beginning with the most electronegative atom. Fill that atom to an octet. Then proceed to the next most electronegative, and so on.

Question 4

Draw a structure for N Cl3

Answer 4

answer: https://www.google.com.tr/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwjZlIO427PRAhUHSBQKHY6NAP0QjRwIBw&url=http%3A%2F%2Fedtech2.boisestate.edu%2Flindabennett1%2F502%2Fcompounds%2520and%2520naming%2Flewis%2520dot.html&psig=AFQjCNHTdLtLncIYZUut4ru4GKpoVviOag&ust=1484004935170880

Question 5

Draw a structure for XeF5

Answer 5

answer: https://www.google.com.tr/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwjwmKnk27PRAhUJvBQKHfZeCkIQjRwIBw&url=https%3A%2F%2Fwww.studyblue.com%2Fnotes%2Fnote%2Fn%2Flewis-structures%2Fdeck%2F12839885&psig=AFQjCNHTdLtLncIYZUut4ru4GKpoVviOag&ust=1484004935170880

Question 6

Draw a structure for CCl4

Answer 6

answer: https://www.google.com.tr/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwjMy_7t27PRAhWGvhQKHWNtAoAQjRwIBw&url=http%3A%2F%2Fwww.biochemhelp.com%2Flewis-dot-structure-diagram-tutorial.html&psig=AFQjCNHTdLtLncIYZUut4ru4GKpoVviOag&ust=1484004935170880