Electrostatic interactions with neighbors cause atoms in solids to be held in place as if bound together by tiny springs. The excitation temperature for vibrations in many metals is around 200 K. If the mass of a metal atom is 2.0 Ã- 10âˆ'25 kg, what is a typical value for the force constant κ (Fspring= âˆ'κx) with which the atoms are bound in place? The answer is 137 N/m. How do you arrive at that conclusion?