In which of the following molecules is the carbon-carbon distance the shortest?

Which of the following combinations of atomic orbitals can overlap to form a $\pi$ bond?

For the molecule $C_2{H}_4$ (ethene), how many sigma ($\sigma$) and pi ($\pi$) bonds are present?

In the molecule $C_2{H}_4$ (ethene), how many $s–{\mathrm{sp}}^2$ sigma bonds are present?

Which of the following molecules contains only $\sigma$ bonds?

In the molecule ethene ($C_2{H}_4$), how many sigma ($\sigma$) and pi ($\pi$) bonds are present?

In $C_2{H}_4$ (ethene), which type of bond is formed by the sideways overlap of p orbitals?

Which types of orbital overlap occur between two adjacent atoms to form a $doublebond$?

Which type of atomic orbitals overlap to form $\pi$ bonds in organic molecules?