How to Draw Lewis Structures Groups Review Group

How to Draw Lewis Structures

Groups Review Group 8 = 8 electrons Group 1 = 1 electron Group 2 = 2 electrons 3, 4, 5, 6, 7 Except for He, it has 2 electrons • Each column is called a “group” • Each element in a group has the same number of electrons in their outer orbital. www. chem 4 kids. com • The electrons in the outer shell are called “valence electrons”

Draw Lewis dot structures. How many valence electrons do each of the following elements have? Ca K O S C Br N

Review-Octet Rule Atoms bond in order to have 8 valence electrons. Exceptions: Hydrogen only needs 2 valence electrons to be complete. Boron is fine with 6 valence electrons Beryllium is fine with 4 electrons

Rules for drawing Lewis Dot Structures 1. Count all the valence electrons for your atoms. 2. Draw the first atom (Second atom if the first is Hydrogen) listed in the center, then connect all other atoms to the center atom with single bonds. 3. Each bond counts as 2 electrons. 4. Complete any octets with remaining electrons. Example: CH 2 Cl 2 C= 4 valence H=1 x 2 valence Cl=7 x 2 valence Total=20 valence

Try these… CH 4 NF 3

Double and triple bonds What happens if you don’t have enough electrons? Make double or triple bonds. Example: CO 2

Try these… OF 2 O 2 N 2 C 2 H 6 C 2 H 4 C 2 H 2 SO 3