Lewis structure of C₂H₄
12 valence electrons. One C=C double bond and two C-H single bonds, with no lone pair on C.
Lewis structure
12 valence electronsFormal charges: none
Why this shape
- Each C has 4 valence electrons. It uses four in one double bond to C and two single bonds to H, so none are left over.
- Steric number = three sigma bonds + no lone pairs = 3, so each C is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
- Three electron pairs point to the corners of a flat triangle (trigonal planar electron geometry). With no lone pairs the atoms take the same shape: trigonal planar.
- All the bond pairs repel each other equally, so the angle is the ideal about 120°.
- The molecule is flat and symmetric, so the C-H bond dipoles cancel.
How to draw it
- Count the valence electrons: 2 × C 4 + 4 × H 1 = 12 valence electrons, 6 pairs.
- Join the atoms with single bonds: the C atoms to each other and the H atoms around them.
- Give each outer atom lone pairs until it has an octet (H needs only two electrons), then put any electrons left over on the central atom.
- Where an atom is still short of an octet, turn a lone pair of its neighbour into a shared pair: that makes a double or triple bond.
- Result: one C=C double bond and two C-H single bonds, with no lone pair on C.
- Formal charge = valence electrons − lone pair electrons − number of bonds. Here: none.
Class 11, Chapter 4 Chemical Bonding and Molecular Structure.
Lewis structure of C2H4: quick answers
How many valence electrons are in C2H4?
2 × C 4 + 4 × H 1 = 12 valence electrons, 6 pairs.
What are the formal charges in the Lewis structure of C2H4?
Every atom has a formal charge of zero.
How many lone pairs are in the Lewis structure of C2H4?
0 in all, none on the central C.