Atomic Structure

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Isotopes are atoms with the same number of protons and electrons but different number of neutrons.

Same atomic number = different mass number.

Have same chemical properties due to same number of electrons.

Have different physical properties due to different number of neutrons.

Isotopes of an element with an increased number of neutrons will have:

Higher masses

Higher densities

Higher melting and boiling points

Relative atomic mass (Ar) of an element is the average mass of its isotopes compared to 1/12 the mass of one atom of carbon-12.

Ar = (Average mass of an atom x 12) / Mass of one atom of carbon-12

Ion is an atom that has either lost or gained an electron thus giving it a charge.

Atom that has lost electrons = positive charge

Atom that has gained electrons = negative charge