Copyright © 2008 Pearson Prentice Hall, Inc.
Chapter 7/
18
Electron-Dot Structures of
Polyatomic Molecules
Draw an electron-dot structure for
CH
2
O
.
4 + 2(1) + 6 = 12 valence electrons
Step 3:
Step 1:
Step 2:
H
C
O
H
H
C
O
H
Step 5:
H
C
O
H
H
C
O
H
Step 2: The least electronegative atom is the central one (hydrogen can’t be the central atom).
Step 3: Two of the terminal atoms are hydrogen.
Step 4: There are no remaining electrons to place on the central atom.
Step 5: “Borrow” a pair from oxygen to complete the central atom’s octet.