The triple bond between two carbon atoms in ethyne is formed by.......

If the internuclear axis is $z$,then which of the following overlapping gives a $\sigma$ bond?

How is the $F_2$ molecule formed?

According to the $VB$ theory,when is a bond not formed between two atoms? Give examples.

Explain the types of overlapping of atomic orbitals with diagrams.

$A$ molecule $(X)$ has $(i)$ four sigma bonds formed by the overlap of $sp^2$ and $s$ orbitals,(ii) one sigma bond formed by $sp^2$ and $sp^2$ orbitals,and (iii) one $\pi$ bond formed by $p_z$ and $p_z$ orbitals. Which of the following is $X$?