Answer:
Step-by-step explanation:
Would you expect metals to have high ionization energies or low ionization energies? Support your answer by relating ionization energy to the formulation of ions.
By natural process, elements individually gain or lose electrons by the path of least resistance to form an element with a Noble Gas electron configuration. That is, elements containing less than 4 electrons (Groups IA through Groups IIIA and include the Transition Elements) tend to lose electrons and become positive cations. Elements containing 4 or more valence electrons generally tend to gain electrons forming negative anions. In general, the elements forming cations are collectively ‘The Metal Elements’ and the elements forming anions are collectively ‘The Nonmetal Elements’.
The chart following the explanation text shows metals in blue, metalloids in green and nonmetals in yellow. In general, metals tend to lose electrons, nonmetals tend to gain electrons and metalloids sometimes gain and sometimes lose depending upon the compound of interest.
(see chart at end of explanation)*
Trends in ionization energy depend upon three factors, 1. Atomic and Ionic Radii, 2. The amount of energy needed (gain/endothermic process) to remove electrons from the element’s electronic structure and 3. ‘Electron Affinity’ an energy term describing the amount of energy lost (exothermic process) when an electron is added into the valence shell of an element.
Atomic and Ionic radii of metals tend to decrease with increasing atomic number. That is, in a given series the 1st element would have the largest atomic and ionic radii and sequentially decrease through the smaller radii as atomic number increases. In order of increasing atomic number the following 1st ionization energies (removal of 1st electron) are known for the listed metallic elements of series 2 of the periodic table:
Li + 520Kj/mole => Li⁺ + eˉ (valence electron is farther away from nucleus than the next two elements in series.)
Be + 900Kj/mole => Be⁺ + eˉ (electronic orbital structure is more stable for the 1st 2eˉs)
B + 801Kj/mole => B⁺ + eˉ (electron orbital structure is less stable (easier to remove) for 3rd electron requiring a lower ΔEᵢ.)
In the series, the elements are increasing in proton and electron number resulting in smaller radii and stronger attractive electrostatic forces (stronger bond) between the nucleus and electron cloud. Relating this trend to the 1st ionization energy values shown above, the larger radii requires lower ionization energies as the valence electron is farther from the nucleus with a weaker bond than subsequent elements in the same series.
In a more fundamental context, consider Lithium (Li) with its 1 valence electron. By path of least resistance concept (see 1st sentence), would it be more reasonable for lithium to gain 7 electrons to achieve a Noble Gas configuration (i.e., Ne) or lose 1 electron to achieve the Noble Gas configuration (i.e., He)? By natural path of least resistance, Li would tend to lose its one valence electron forming the cation Li⁺. Of course, with a little thought, gaining 7 electrons would be improbable as lithium has only 3 protons (+); certainly not enough attractive force to hold 8 electrons (1e⁻ + 7e⁻ gained).