Given a scientific passage and an answer, generate a question for the given answer.

Passage: Figure 2.22 When carbon forms single bonds with other atoms, the shape is tetrahedral. When two carbon atoms form a double bond, the shape is planar, or flat. Single bonds, like those found in ethane, are able to rotate. Double bonds, like those found in ethene cannot rotate, so the atoms on either side are locked in place. Answer: carbon
When what common element forms single bonds with other atoms, the shape is tetrahedral, and when its atoms form a double bond, the shape is planar?