Atoms will gain, lose, or share electrons to match the number of outer shell electrons of a noble gas.
Atoms can achieve a stable outer electron arrangement by gaining, losing or sharing valence electrons with other atoms or ions.
They don't have one. Group 8 is noble gasses.
Ions are formed when elements gain or lose electrons.
stable atomic structure
There are three different ways for this. Elements can either gain electrons or lose electrons or share electrons and attain a stable noble gas electronic configuration.
Many of the elements with higher atomic numbers have no stable form yet discovered, ex: ununoctium.
All elements above the atomic number of 83 are radioactive, but two elements that are under it are also radioactive. They are technetium (atomic number 43) and promethium (atomic number 61). Radioactive elements are elements that decay until stable. =)
All isotopes of all elements with atomic number similar or greater than 84 are radioactive, and don't have stable nuclei.
Only up through bismuth.
A stable element is any non-radioactive element. All elements before element atomic number 84 (not including 84) - Polonium (Po) are stable elements.
All the elements has an atomic weight; sometimes for the unstable radioactive elements is indicated only the value of the atomic mass of the most stable isotope.The term atomic weight is used for elements and the term atomic mass for isotopes (after the rules and the tradition of IUPAC).
It really isn't elements that are stable or unstable, but isotopes. Carbon has both stable and unstable isotopes.