Nuclear Arrangement

1. IsotoPes – atoms or elements that have the same # of protons; same element/atomic number, different mass number

Ex. ¹³⁰₅₆Ba, ¹³²₅₆Ba, ¹³⁵₅₆Ba

2. IsobArs – atoms or elements that have the same atomic mass.

Ex. ¹³¹₅₃I, ¹³¹₅₄Xe, ¹³¹₅₅Cs

3. IsotoNes – atoms or elements that have the same # of neutrons

Ex. ¹²⁹₅₃I, ¹³⁰₅₄Xe, ¹³¹₅₅Cs

4. IsomErs – atoms or elements that have the same atomic mass and atomic number but differs in energy levels.

Ex. ⁹⁹₄₃Tc, ^99-m₄₃Tc

Note: Use the mnemonic PANE to easily identify what type of nuclear arrangement is given.

P- for Isotope; means the same number or protons (atomic number)

A- for Isobars; means the same atomic mass number

N- for Isotones; means the same number of neutrons

E- for Isomers; means only differ in energy levels (usually represented by superscript “m”)

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