1.1. State a property that distinguishes a lepton from other subatomic particles.

1.2. Table 1 gives information about some leptons.

 Table 1

 Complete Table 1 by filling in the missing information.

1.3. A negative muon (${ \mu }^{-}$) may decay into three leptons             

Complete the equation representing the muon decay.

1.4. Particle physics is a collaborative effort and there are have been considerable advances in this field over the past 100 years. 

 Explain why it is necessary for large teams of scientists and engineers to collaborate and validate new knowledge for these advances to occur.