What determines the flame color of a metal?

The flame color of a metal is determined by the specific wavelengths of light emitted when the metal's electrons are excited and then return to their ground state. When heated, the electrons absorb energy and jump to higher energy levels; as they fall back, they release energy in the form of light. Each metal has a unique electron configuration, leading to distinct colors based on the energy differences between electron levels. Common examples include sodium producing a bright yellow flame and copper yielding green or blue flames.