Changes

: Each [[element]] has many [[isotope]]s but some are [[Stable Isotope|stable]] and others are [[Unstable Isotope|unstable]] so they [[Radioactive Decay|decay]] quickly into other [[isotope]]s or a different [[element]].

: Different [[isotope]]s of the same [[element]] have the same [[Atomic Number|atomic number]] but different [[Relative Atomic Mass|atomic mass]] due to the different numbers of [[neutron]]s.

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| style="height:20px; width:200px; text-align:center;" |'''Hydrogen-1'''