The number of electrons that an element will gain or lose depends on what factors?

Imma say go with a (:

The law of conservation of momentum will be the same no matter where you apply it.the equation will be  77.4 + m (mass of canister) *3.6

Jenny and fred both play a long note on their trombones. a stationary observer hears the sound increasing and decreasing repeatedly in loudness. which of these must be true? the sound waves from the two trombones have slightly different frequencies.the sound waves from the two trombones have the same frequency.the sound waves from the two trombones have slightly different amplitudes.the sound waves from the two trombones have the same wavelength.the sound waves from the two trombones have slightly different velocities.  lolthe answer is          the sound waves from the two trombones have slightly different frequencies.