Double and triple bonds: O₂, N₂, CO₂ and C₂H₄

4 minAS Level3.4.1

AI-drafted, independently checked · not yet teacher-reviewed

By the end of this lesson

By the end you can describe the double and triple covalent bonds in $\text{O}_2$ , $\text{N}_2$ , $\text{CO}_2$ and $\text{C}_2\text{H}_4$ , and count their shared pairs and lone pairs.

One pair isn't always enough

Oxygen has 6 outer electrons, so it needs 2 more. One shared pair only gets it to 7.

The fix: share two pairs. Two shared pairs between the same two atoms make a double bond, drawn $=$ . Three shared pairs make a triple bond, drawn $\equiv$ .

The rule from last time still works

Bonds an atom forms = electrons it needs to reach 8.

atom	outer electrons	needs	so it can make
O	6	2	one double bond (or two single bonds)
N	5	3	one triple bond (or three single bonds)
C	4	4	four bonds in any mix: e.g. two doubles, or one double + two singles

Quick check

Multiple choiceQuestion 1 · Recall

Answer the question above to continue.