Trends in Ionization Energy

Trends in Ionization Energy
Period trends
All the atoms in the same period have the same valence energy level and the same shielding. The increasing nuclear charge increases the attraction of valence electrons so ionization energy generally increases from left to right. The exceptions at full and ½ filled orbitals break the pattern because removing an electron from a stable (low energy) configuration will require more energy. Li has a low 1st ionization because 2 core electrons block the +3 nuclear charge more than they could block the +10 nuclear charge in the Ne atom that would have large ionization energy.
Trends in Electron Affinity
Period trends
Electron affinity is low for metals and high for nonmetals. It is easiest for group 7Ato get and hold an extra electron because it gets them to full energy level. Electron affinity increases from left to right as atoms become smaller, with greater nuclear charge and get closer to a full energy level. http://hrsbstaff.ednet.ns.ca/benoitn/chem11/units/review/periodic_table/trends_p_table.htm• The electrons in the outer shell are called valence electrons.
• Valence electrons are found in the outermost shell of an atom and that determines the atom’s chemical properties.
• Elements with the same number of valence electrons tend to react in similar ways.
• Because s and p electrons fill sequentially
• A horizontal row on the periodic table is called a period. Elements in the same period have the same number of occupied energy levels. http://www.oakland.k12.mi.us/Portals/0/Learning/PeriodicTable.pdfThe electrons in the partially filled outermost shell (or shells) determine the chemical properties of the atom; it is called the valence shell.
Periods 1, 2, & 3
The first three rows of the periodic table, called periods 1, 2 and 3, corresponding to the n=1, n=2 and n=3 levels, visible in the green numbers to the left. Hydrogen is seen to have 1 electron in the 1s level, and to the right, helium, in Group 18, has 2 electrons in the 1s level, a completely filled shell, the "duet rule." Helium is the first in the series of "noble gases." Moving down to period 2, lithium is the first element in the row, with a filled 1s configuration (denoted by the [He] prior to the 2s1 notation). The [He] is carried across the period as first the 2s and then the 2p orbitals fill, arriving at the configuration for neon, following the "octet rule". Period 3 follows a similar pattern. Please note that the number of outer-shell electrons, which is represented as the righmost digit in the group number, is the major determinant of the elements valence, thus, this is the valence orbital. https://www.boundless.com/chemistry/periodic-properties/the-history-of-the-periodic-table/periodic-table-position-and-electron-configuration/The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. http://en.wikipedia.org/wiki/Period_3_elementThe table is arranged into groups (columns) by the number of electrons in the outer electron field. So Na in grp. I has only 1 outer electron, whereas Cl in grp. VII has 7. From left to right are periods of increasing atomic number.
The groups are very important for understanding how any element will behave. The elements in each group share similar characteristics because they have the same number of outer electrons, so react similarly. Despite this, the reaction rate varies as you go down the periods because the distance between the outside electrons and the atom nucleus gets greater.
Acid-Base Properties of Oxides
Those oxides that are produced in the reactions above have various physical properties. Sodium and magnesium oxides have ionic structures and silicon, phosphorous and sulphur oxides have covalent bonding. Aluminium oxide on the other hand, has a type of boding that is somewhere in between. Since aluminium has a very high charge density it is able to distort the electron cloud so that aluminium oxide has a very covalent character.
In the table below are the reactions of period 3 oxides with water, with the resulting pH.You will notice that the trend in the pH of the solutions formed goes from alkaline to acidic. This is because the less electronegative sodium has a weak Na-O bond and the oxygen is more easily given up to reacts with H+. Further along though, a strong S-O bond keeps this together and more H+ is generated. The amphoteric aluminium oxide has a bonding which is both ionic and covalent in nature.
When these oxides are reacted with acids or bases, a neutralisation would occur with a salt and water produced. Aluminium oxide is amphoteric, meaning it reacts with both acids and bases. http://scienceaid.co.uk/chemistry/inorganic/thetable.html Metallic character
"Tendency of an atom to form positive ions by losing electrons is called its metallic character."
The more readily an atom loses electrons, the more metallic it is.
The metallic character of elements decreases as we move across a row from left to right in the periodic table and increases as we move down a column in the periodic table. This is because on moving across a row in the periodic table, the number of valence electrons increases which causes elements to gain electrons rather than losing them. When we move down a column in the periodic table, the metallic character increases because the number of valence electrons remains same and the atomic size increases which makes the valence electrons more far away from the nuclear attraction and thus easier to lose. http://chemistry.tutorvista.com/inorganic-chemistry/trends-in-the-periodic-table.html#properties-of-trends-in-periodic-tableAs we go across a period
1. The outermost electrons are about the same distance from the nucleus
2. There is very little additional shielding.
3. The atom gets smaller
4. The outermost electrons are held more tightly.
5. Reactivity as a nonmetal increases. http://apbrwww5.apsu.edu/robertsonr/chem1110-20/PeriodicTable%20trends_red.pdfFreudenrich, Ph.D., Craig. "How the Periodic Table Works" 28 January 2009. HowStuffWorks.com. <http://science.howstuffworks.com/periodic-table.htm> 09 September 2013.
Chemical Reactivity:
METALS
DOWN a Group: In METALS reactivity INCREASES as you go DOWN a Group because the farther down a Group of metals you go, the easier it is for electrons to be given or taken away, resulting in higher reactivity.
ACROSS a Period: In METALS reactivity DECREASES as you go ACROSS a Period because though they still want to give away valence electrons they have more of them to get rid of, which requires more energy. Not as easy to blow off a little steam!
NON-METALS
UP a Group: In NON-METALS reactivity INCREASES as you go UP a Group because the higher up and to the right atoms are, the higher the electronegativity, resulting in a more vigorous exchange of electrons. Fluorine? A greedy, impatient beast when it comes to electron exchange manners.
ACROSS a Period: In NON-METALS reactivity INCREASES as you go ACROSS a Period because (notice how trends repeat?) the closer you get to fulling your s- and p- orbitals the more motivated you are to do so. http://edtech2.boisestate.edu/lindabennett1/502/Periodic%20Table%20e%20config/PTable_trends%20around%20table.htmlMetals are generally shiny, malleable, and hard. Metals are also good conductors of electricity. Examples of metals are Gold, Silver, Iron, Uranium, and Zinc.
Non-metals do not conduct heat or electricity very well. Non-metals are typically brittle and are not easily molded into shapes. Example non-metal elements are Hydrogen and Carbon.
Metalloids share characteristics of both metals and non-metals and are also called semimetals. Metalloids are typically semi-conductors, which means that they both insulate and conduct electricity. This semi-conducting property makes Metalloids very useful as a computer chip material. Examples of metalloid elements are Silicon and Boron. http://www.cliffsnotes.com/cliffsnotes/sciences/what-are-two-properties-of-metals-nonmetals-and-metalloidsMetallic properties, non-metallic properties, which third row elements
Statement relating the metallic and non-metallic properties of the element to their position in the periodic table
Infer the color of the indicator in acidic and basic solutions
Classify solutions of each oxides as acid or basic
Statement relating the acid and basic properties of the element to their position in the periodic table
Relate 2 and 5