Answer:
False
Step-by-step explanation:
After creating a synthetic element in the laboratory, scientists are able to determine the properties of these elements through tests and quick analyzes that are generally based on the observation of the melting point presented by that element and what is the electrical and thermal conductivity of it.
These tests are simple and quick, being performed as soon as the element is created. For this reason, we can disagree with the claim that scientists do not know the properties of the elements they create.