Final answer:
Methane (CH4) has a tetrahedral geometry, with a central carbon atom bonded to four hydrogen atoms, and is uniquely positioned at 109.5° angles from each other.
Step-by-step explanation:
The molecule among the options provided that has a tetrahedral geometry is methane, CH4. Tetrahedral geometry refers to a molecular shape where a central atom is bonded to four peripheral atoms, positioned at the vertices of a tetrahedron. Methane fits this description perfectly, with a central carbon atom bonded to four hydrogen atoms. This tetrahedral arrangement in methane places the hydrogen atoms at 109.5° angles with respect to each other.
While molecules like water (H2O) and ammonia (NH3) also have four electron groups around the central atom, they do not exhibit tetrahedral geometry due to the presence of lone pairs. Water has a bent shape, and ammonia has a trigonal pyramidal shape because of these lone pairs distorting the geometry. Carbon dioxide (CO2) has a linear geometry due to its double bonds and no lone pairs on the central atom.