Vocabulary
Ions
species with an overall charge
What is the first step in drawing a Lewis structure?
Determine the number of total valence electrons for the molecule. For anions, add additional electrons. For cations, subtract electrons.
Covalent bond
two atoms share a pair of electrons
O
What is the second step in drawing a Lewis structure?
Frame the structure through sharing pairs of electrons.
All atoms in the molecule are connected by a pair of bonding electrons. The central atom is typically towards the bottom-left of the periodic table. Add hydrogens last since it can only make one bond.
Octet rule
atoms are stabilized by having 8 electrons in their valence shell
What is the third step in drawing a Lewis structure?
Complete the octets by adding nonbonding pairs of electrons. Start with outer atoms, adding lone pair electrons
Lewis structure
shows valence structures and covalently bonded atoms
Cl
7
What is the fourth step in drawing a Lewis structure?
Assign remaining electrons (if any) to the central atom. If not enough electrons remain, try double or triple bonds. The goal is that every atom has a full octet.
What is the equation for formal charge?
formal charge of an atom = (valence electrons in the neutral atom) - (number of covalent bonds) - (number of unshared electrons)
Fe
Hint: 1s22s22p63s23p64s23d6
Answer: 2
What is the fifth step in drawing a Lewis structure?
Assign formal charges if necessary.