The shapes of methane, ethene and ethyne molecules are, respectively

The shapes of methane, ethene, and ethyne molecules are tetrahedral, trigonal planar, and linear, respectively.

1. Methane (CH4): The central atom (Carbon) is surrounded by four hydrogen atoms. According to the VSEPR theory, the electron pairs around the central atom will arrange themselves in a way that minimizes repulsion, resulting in a tetrahedral shape.

2. Ethene (C2H4): Each carbon atom is bonded to three other atoms (two Hydrogen and one Carbon), resulting in a trigonal planar shape.

3. Ethyne (C2H2): Each carbon atom is bonded to one Hydrogen atom and triple-bonded to the other Carbon atom, resulting in a linear shape.