3

• The p-type dopant elements are: boron, aluminum, gallium, and indium.
• The n-type dopant elements are: nitrogen, phosphorus, arsenic, and antimony.

[3.50 / 1,000,000] * 147 kg = ....... kg (finish it by yourself) = 514.5 mg

No. The NPN transistor is a semiconductor crystal that was "doped" with n-type dopant, then p-type dopant, and then n-type dopant during manufacture. Just the opposite is true for the PNP transistor. Once it's made, it can't be "unmade" to change it.

Phosphorus.

(And Boron for p-type)