Hello Student,

Your question can be answered by the Heisenberg Uncertainty Principle. It states that that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory. Hence, any for object, at given point in time, the position of the object can be found if the momentum is not found. And vice versa.

Here since you have mentioned that the certainty of position of electron is zero, it would mean that the velocity, or by extension the momentum of the electron is known accurately. This means that the certainty of the momentum would be infinite. Hence the uncertainty of momentum is zero.