Electron Configuration
And Periodic Properties
Atomic Radii
atomic radius- one-half the distances between nuclei of identical atoms that are bonded together.
Period Trends
The trends to smaller atoms across a period is caused by the increasing positive charge of the nucleus.
Group Trends
In general, the atomic radii of the main-group elements increase down a group
Ionization Energy
A+ + e- (A+ = ion with a single positive charge)
ionization- any process that results in the formation of an ion
Ionization energy (IE)- the energy required to remove one electron from a neutral atom of an element
Period Trends
Ionization energies of the main-group elements increase across each period
Group Trends
Among the main-group elements, ionization energy generally decrease down the groups
Removing Electrons from Positive Ions
- Each successive electron removed from an ion feels an increasingly stronger effective nuclear charge (the nuclear charge minus the electron shielding)
Electron Affinity
Electron affinity - energy change that occurs when an electron is acquired by a neutral atom
A + e- ⇒ A- +energy
A + e- + energy ⇒ A-
Period Trends
As electrons add to the same p sublevel of atoms with increasing nuclear charge, electron
exception - between Groups 14&15
Group Trends
electrons add with greater difficulty down a group
Adding Electrons to Negative Ions
- second electron affinities are all positive
Ionic Radii
cation - positive ion
anion - negative ion
Period Trends
left (cations) ⇒ right (anions)
Group Trends
- Gradual increase of atomic radii down a group
Valence Electron
Electronegativity
Electronegativity - measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound
Linus Pauling
Period Trends
Electronegativities tend to increase across each period, although there are exceptions
- Electronegativities tend to either decrease down a group or remain about the same
Periodic Properties of the d- and f-block elements
Atomic Radii
As the number of electrons in the d sublevel increase, the radii increase because of repulsion among the electrons
Ionization Energy
Ionization energies of the d-block and f-block elements generally increase across the periods
Ion Formation and Ionic Radii
Electrons in the highest occupied sublevel are always removed first
Electronegativity
- The general trend for electronegativity values to increase as radii decrease
Brandi Hageman & Kaitlyn Imoehl
Works Cited
Sciencefourms.net, 2013. Web. 25 Oct. 2013.
Davis, R., Frey, R., Sarquis, M., & Sarquis, J. (2009). Modern chemistry. Orlando, FL: Holt, Rinehart, and Winsten.
"Electron Affinity Trends." Grandinetti Laboratory. Drupal, n.d. Web. 25 Oct. 2013.
"Elements, Atomic Radii and the Periodic Table." Crystal Maker Software. Crystal Maker, 2013. Web. 25 Oct. 2013.
"Periodic Trends." Chemwiki. University of California, n.d. Web. 25 Oct. 2013.
"Valence Electrons Periodic Table." TutorVista.com. NCS Pearson, 2013. Web. 25 Oct. 2013.
"What Is “Electronegativity” ?" LifeSun. Mantra&WordPress, n.d. Web. 25 Oct. 2013.