To solve this problem, we need to understand the relationship between the total energy, kinetic energy, and potential energy of an electron in an atom.$\\$The total energy $(E)$ of an electron in an orbit is given as $-3.4$ eV.$\\$In atomic physics, the total energy of an electron in an orbit is the sum of its kinetic energy $(K)$ and potential energy $(U): \\ E = K + U \\$For an electron in a stable orbit, the kinetic energy is positive and equal in magnitude to half the potential energy, but opposite in sign:$\\ K = -\frac{U}{2} \\$The total energy is given by:$\\ E = K + U = -\frac{U}{2} + U = \frac{U}{2} \\$Given that $E = -3.4$ eV, we can substitute this into the equation:$\\ -3.4 = \frac{U}{2} \\$Solving for $U: \\ U = 2 \times (-3.4) = -6.8$ eV$\\$Now, using the relationship between kinetic and potential energy:$\\ K = -\frac{U}{2} = -\frac{-6.8}{2} = 3.4$ eV$\\$Thus, the kinetic energy is $3.4$ eV and the potential energy is $-6.8$ eV.$\\$Therefore, the correct option is Option 3: $3.4$ eV, $-6.8$ eV.