compare atomic/ionic of a neutral atom, cations and anions with the help of transfer of electrons and electronic configuration
Answers
Explanation:
Learning Objective
Predict whether an atom will undergo ionization to provide an anion or cation based on its valence shell electron configuration.
Key Points
The electronic configuration of many ions is that of the closest noble gas to them in the periodic table.
An anion is an ion that has gained one or more electrons, acquiring a negative charge.
A cation is an ion that has lost one or more electrons, gaining a positive charge.
Terms
cationA positively charged ion, as opposed to an anion.
ionizationAny process that leads to the dissociation of a neutral atom or molecule into charged particles (ions).
anionA negatively charged ion, as opposed to a cation
Cations and Anions form from Neutral Atoms
Every atom in its ground state is uncharged. It has, according to its atomic number, the same number of protons and electrons. Electrons are rather labile, however, and an atom will often gain or lose them depending on its electronegativity. The driving force for such gain or loss of electrons is the energetically optimal state of having a full valence (outermost) shell of electrons. In such a state, the resulting charged atom has the electron configuration of a noble gas.
Addition of an electron will disrupt the proton-electron balance and leave the atom negatively charged. Removal of an electron will, conversely, leave the atom positively charged. These charged atoms are known as ions.
Formation of Monatomic Ions
Monatomic ions are formed by the addition or removal of electrons from an atom’s valence shell. The inner shells of an atom are filled with electrons that are tightly bound to the positively charged atomic nucleus and so do not participate in this kind of chemical interaction, but the valence shell can be very reactive depending on the atom and its electron configuration. The process of gaining or losing electrons from a neutral atom or molecule is called ionization.
Atoms can be ionized by bombardment with radiation, but the more purely chemical process of ionization is the transfer of electrons between atoms or molecules. This transfer is driven by the stabilization that comes by obtaining stable (full shell) electronic configurations. Atoms will gain or lose electrons depending on which action takes the least energy.
For example, Group 1 element sodium (Na) has a single electron in its valence shell, with full shells of 2 and 8 electrons beneath. Removal of this one electron leaves sodium stable: Its outermost shell now contains eight electrons, giving sodium the electron configuration of neon. Having gained a positive charge, the sodium ion is called a cation. The ionization of sodium can be chemically illustrated as follows: