a) What is the meaning of the acronym „EI“?
EI stands for electron ionization, the former term electron impact is also still in use.
b) EI chiefly creates singly charged ions; however, doubly and triply charged ions may also occur. Which of these are radical ions?
Singly charged: M+., radical ion.
Doubly charged: M2+, even-electron ion.
Triply charged: M3+., radical ion.