Answer:
[tex]-3.2\cdot 10^{-19}C[/tex]
Step-by-step explanation:
- Protons are positively charged particles contained in the nucleus of the atom. They have a charge of [tex]q_p=+1.6\cdot 10^{-19}C[/tex]
- Electrons are negatively charged particles orbiting around the nucleus of the atom. They have a charge of [tex]q_e = -1.6\cdot 10^{-19}C[/tex]
For a neutral atom, the number of protons is equal to the number of electrons, so the total charge of a neutral atom is:
[tex]Q=Nq_p + Nq_e = N(q_p+q_e)=N(+1.6\cdot 10^{-19}-1.6\cdot 10^{-19})=0[/tex]
In this problem, we have an atom having an excess of 2 electrons, i.e. it has 2 more electrons than protons.
Therefore, the charge of this atom will be:
[tex]Q=0+2q_e[/tex]
and substittuing, we find
[tex]Q=2(-1.6\cdot 10^{-19})=-3.2\cdot 10^{-19}C[/tex]