#As element electron configuration full

Click here for an exampleįor example, iron (1s 22s 22p 63s 23p 63d 64s 2) forms the ion Fe2+ (1s 22s 22p 63s 23p 63d 6) by the loss of the 4s electron and the ion Fe3+ (1s 22s 22p 63s 23p 63d 5) by the loss of the 4s electron and one of the 3d electrons. Most transition metal cations have 2+ or 3+ charges that result from the loss of their outermost s electron(s) first, sometimes followed by the loss of one or two d electrons from the next-to-outermost shell. Transition and inner transition metal elements behave differently than main group elements. Mercury (group 12) also exhibits an unexpected behavior: it forms a diatomic ion, Hg 2 2+ (an ion formed from two mercury atoms, with an Hg-Hg bond), in addition to the expected monatomic ion Hg 2+ (formed from only one mercury atom). The formation of these 1+, 2+, and 3+ cations is ascribed to the inert pair effect, which reflects the relatively low energy of the valence s-electron pair for atoms of the heavy elements of groups 13, 14, and 15. In addition to the expected ions Tl 3+, Sn 4+, Pb 4+, and Bi 5+, a partial loss of these atoms’ valence shell electrons can also lead to the formation of Tl +, Sn 2+, Pb 2+, and Bi 3+ ions.

Click here to learn more!Įxceptions to the expected behavior involve elements toward the bottom of the groups. For example, aluminum (in group 13) forms 3+ ions (Al 3+).Īs always, there are exceptions. Thus, the charge of a cation formed by the loss of all valence electrons is equal to the group number minus 10.

#As element electron configuration full

The Ca 2+ ion is therefore isoelectronic with the noble gas Ar.įor groups 13–17, the group numbers exceed the number of valence electrons by 10 (accounting for the possibility of full d subshells in atoms of elements in the fourth and greater periods). When a Ca atom loses both of its valence electrons, the result is a cation with 18 electrons, a 2+ charge, and an electron configuration of 1 s 22 s 22 p 63 s 23 p 6. For example, calcium is a group 2 element whose neutral atoms have 20 electrons and a ground-state electron configuration of 1 s 22 s 22 p 63 s 23 p 64 s 2. For groups 1 (the alkali metals) and 2 (the alkaline earth metals), the group numbers are equal to the numbers of valence shell electrons and, consequently, to the charges of the cations formed from atoms of these elements when all valence shell electrons are removed. When forming a cation, an atom of a main group element tends to lose all of its valence electrons, thus becoming isoelectronic with the previous noble gas in the periodic table. Electronic structures of CationsĪ cation (positively charged ion) forms when one or more electrons are removed from a parent atom. Ions are formed when atoms gain or lose electrons.