4) What is the difference between an atom and an ion?

 Explanation:

Atom means the smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.

Iron means a common, inexpensive metal, often black in color, that rusts, is attracted by magnets, and is used in making steel.

Atoms are neutrally charged; they contain the same number of protons as electrons. By definition, an ion is an electrically charged particle produced by either removing electrons from a neutral atom to give a positive ion or adding electrons to a neutral atom to give a negative ion.

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