Atomic Structure: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Atomic Structure. Understanding the underlying formula is key to arriving at the correct answer below:

For an electron in an orbit, its kinetic energy is the negative of its total energy ($K = -E$). Given the total energy is $-3.4 eV$, its kinetic energy is $-(-3.4 eV) = 3.4 eV$.