Final answer:
Atoms often gain, lose, or share electrons to achieve the same number of electrons as the noble gas closest to them in the periodic table. This is influenced by the ionization energy and electron affinity of the atom.
Step-by-step explanation:
Atoms often gain, lose, or share electrons to achieve the same number of electrons as the noble gas closest to them in the periodic table. This is determined by two factors: the atom's ionization energy, which measures how strongly the atom holds on to its own electrons, and the atom's electron affinity, which measures how strongly the atom attracts other electrons. In general, atoms with high ionization energy and low electron affinity are more likely to lose electrons, while atoms with low ionization energy and high electron affinity are more likely to gain electrons.