# Question #4c3aa

Feb 6, 2015

For neutral atoms, you'll always have a net charge equal to zero. This happens because a neutral atom has equal numbers of protons and electrons.

Elements are listed in the periodic table in order of their atomic numbers, symbol $\text{Z}$, which represent the number of protons they have in their nucleus. So, for a neutral atom, the number of electrons will be equal to that atom's atomic number.

${\text{number of e}}^{-} = Z$ $\to$ for neutral atoms

The number of neutrons an atom has in its nucleus is determined by using its mass number, symbol $\text{A}$, which represents the total number of protons and neutrons that atom has. Therefore, you can determine how many neutrons you have by using

$\text{neutrons" = "[mass number](http://socratic.org/chemistry/a-first-introduction-to-matter/mass-number)" - "atomic number}$

which is equivalent to

$N = A - Z = \left(N + p\right) - p$ - protons plus neutrons minus protons.

So, for any element in the periodic table, you'll have

Net charge is determined by comparing the number of protons and the number of electrons an atom has. So,

$\text{Z" - "number of electrons" = "net charge}$

I'll redirect you to a more detailed answer on determining net charge because I don't want this answer to become very long:

http://socratic.org/questions/i-want-to-know-how-to-get-the-net-charge-for-each-element