1. Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the naturally occurring electrons is removed. The radius of the orbit is 2.40 10^-11 m. Determine the magnitude of the electron's centripetal acceleration.

2. A single electron orbits a lithium nucleus that contains three protons (+3e). The radius of the orbit is 2.98 10^-11 m. Determine the kinetic energy of the electron.