Answer
The period of this pendulum is still $1.5~s$
Work Step by Step
We can write an expression for the original period of the pendulum:
$T = 2\pi~\sqrt{\frac{L}{g}}$
The period does not depend on the mass or the amplitude, so changing the mass and the amplitude does not affect the period.
The period of this pendulum is still $1.5~s$
