Elements and Atoms

element-an element is a substance that cannot be broken down into other substances by ordinary chemical reactions.

For example: oxygen (O), sodium (Na), carbon (C)

atom-an atom is the smallest unti of matter that still retains the property of an element.

In the figure below are depicted a Nitrogen and Oxygen atom.

The Nitrogen atom has 5 electrons in the outermost valance orbital, and two electrons in the inner orbital for a total of 7 electrons. In addition there are 7 protons (P+) in the nucleus of the atom.

The Oxygen atom has 6 electrons in the outer valance orbital and two electrons in the inner orbita for a total of 8 electrons. In addition therer are 8 protons in the nucleus of the oxygen atom.