Chapter 18, Problem 1P

Iron atoms have been detected in the sun's outer atmosphere, some with many of their electrons stripped away. What is the net electric charge (in coulombs) of an iron atom with 26 protons and 7 electrons? Be sure to include the algebraic sign (+ or -) in your answer.

To determine

The net electric charge of an atom having 26 protons nd 7 electrons.

Answer to Problem 1P

  $3.04\times {10}^{-18}\text{ C}$

Explanation of Solution

Given:

The iron atom contains number of protons say $\left(n_p\right)=26$ and number of electrons say $\left(n_e\right)=7$ .

Formula used:

The net electric charge $\left(q\right)$ on an atom is given by the formula:

  $q=\left(n_p-n_e\right)e,$ where $e=1.6\times {10}^{-19}\text{ C}$ .

Calculation:

Plugging for $\left(n_p\right)=26$ , $\left(n_e\right)=7$ and $e=1.6\times {10}^{-19}\text{ C}$ in formula stated above to find the net find the net electric charge $\left(q\right)$ on the iron atom. Therefore, the net electric charge $\left(q\right)$ is evaluated as:

  $\begin{array}{c}q=\left(\left(26\right)-\left(7\right)\right)\left(1.6\times {10}^{-19}\right)\\ =\left(19\right)\left(1.6\times {10}^{-19}\right)\\ =3.04\times {10}^{-18}\text{ C}\end{array}$

Conclusion:

The net electric charge on the iron atom is $3.04\times {10}^{-18}\text{ C}$ .