The period is the time it takes the pendulum to make one complete swing. If takes the pendulum 1 s to move from one extreme to the other, it take same time to come back- that total time is 2 s.

If you are expected to answer a question like this, you probably have a formula in your text or notes that connects the period with the length of the pendulum, l, and the gravitational acceleration, g. You probably are only expected to answer whether the time period increases or decreases. Is g in the numerator or denominator in that formula?