by definition , frequency is the rate at which disturbance is made through a medium. hence when rate at which disturbance is made doubled, the frequency also gets doubled,
Time period is given as
T = 1/f where T = time period , f = frequency
so when frequency is doubled , Time period becomes half , since Time period is inversely related to the frequency.
Amplitude does not depend on frequency hence amplitude remains unchanged .
wavelength is given as
λ = v/f
Wavelength becomes half when the frequency is doubled since wavelength is inversely related to frequency and speed is constant.