Question

An alpha particle consists of two protons and two
neutrons. What is the charge of an alpha particle?
(1) 1.25 × 10^19 C (3) 6.40 × 10^–19 C
(2) 2.00 C (4) 3.20 × 10^–19 C

Answer 1

     The Elementary Charge is given by:

$e=1.6*10^{-19}$
 
     In the alpha particle there are two protons, so the total charge will be:

$C=e+e \\ C=2*1.6*10^{-19} \\ \boxed {C=3.2*10^{-19}}$
 
     Remember that the neutron has no charge, therefore not appear in the calculation.

Number 4
  
If you notice any mistake in my english, please let me know, because i am not native.