1. Periodically Trending Tables By Andrew Reyes, Prithvi Iyer, Dulguun Enkhbayar, and Dylan San Gabriel

2. What is the Atomic Radius? There are multiple different accepted definitions of the atomic radius, but the most common definition is described as the atomic radius of an element is the distance of a straight line from the center of the nucleus to the edge of its electron cloud. Trends concerning the atomic radius of an element and a period in the periodic table The trend of the atomic radius is unnoticable at a glance. It will become easier to notice the trend if the observer reads the table period by period. If read period by period, the trend becomes obvious that the atomic radius is increasing as it is nearing the left side of the table and decreasing as it moves to the right. How does this trend work? The reason why this trend works is because of the configuration of electrons in each element. Because of the periodic table’s arrangement, it happens to place each element that starts a new electron orbit right at the start of the period. This means that the difference between the atomic radius of a noble gas(end of each period) and an alkali metal(start of each period) is significant due to the new electron orbit Atomic Radii

3. Atomic Radii (continued) Trends concerning the atomic radius of an element and a group in the periodic table: Like the trend across a period, this trend will be difficult to notice at first, but it will become very easy to notice after linking the trend with the electron configuration of the element, just like with the trend across the period. Similar to the trend across the period, the atomic radius increases as the group moves down, and vice versa. How does this trend work? The reason why this trend works is fairly due to the arrangement of the element, similar to the trend in the periods of the table. For example, element B, which happens to be under element A, would have a much bigger atomic radius than element A, because element B has one or two more electron orbits depending on the positions of the elements in the table It is also very difficult to find the atomic radius of an element because of the way the electrons behave. Thanks to Erwin Schrödinger, we know that the electrons in an element move erratically around the nucleus, forming a cloud. Due to the cloud, there is no definite boundary

4. Ionization Energy Ionization energy is defined as an amount of energy required to remove the valence electron to form a cation. As the atomic number increases in a period, so does the ionization energy. This is seen because elements on the right side of the table have nearly filled valence electrons and left side is more willing to lose. Ionization Energy Trends in the Periodic Table Grandinetti, Phillip J. “Ionization Energy Trends.” Ionization Energy Trends, PhySy, www.grandinetti.org/ionization-energ y-trends.

5. Ionization Energy (continued) Trends on the groups increases from bottom to top due to electron shielding. Electron Shielding is described as the ability of an atom’s inner electron shield its positively-charged nucleus from its valence electrons. As shielding decrease it becomes easier to cationized, thus increasing up a group.

6. Electronegativity Decreases Increases Electronegativity indicates the relative ability of an atom to attract electrons in a chemical bond. F is the highest Scale of electron negativities allow for chemists to evaluate the electron affinity of certain atoms when in a compound Electronegativity Values for Representative Elements / Electron Affinity Electron affinity: measure of the tendency of atom to accept an electron *Electronegativities and electron affinities share the same trends* *Same concept with Periodic table* Electronegativity values are values comparing the abilities of atoms to attract shared e - with the ability of fluorine Fr is the lowest

7. Electronegativity (continued) “Electronegativity vs Atomic Number.” Electronegativity vs Atomic Number, Geocities, www.geocities.ws/junebug_sophia/elecN.htm. Excluding noble gases, electron affinity ↑ as the atomic number ↑ within a given period. This trend results from the increase in nuclear charge and the atomic radius decrease, the increased attraction makes it easier for the atom to attract the electron. Electron affinity ↓ with an ↑ in atomic number within a group. Trend is occurs due to the addition of another principal energy level which results in the electron being further from the nucleus and the decreased attraction challenges the atom into attract the electron

8. Metallic Character Metallic Element: Elements that are usually shiny solids that have the ability to conduct heat or electricity Properties the certain types of elements hold are, its shiny appearance, metallic luster, high thermal conductivity, and high electrical conductivity Melting points of metals vary During the boiling process of elements, atoms must be separated from cations/e - which requires a great amount of energy Metals are malleable and ductile Non metallic element: Elements that do not have the characteristics of metals such as luster, malleability, high thermal conductivity, and high electrical conductivity Non-metallic elements contain high ionization properties, high electronegativities, little or no metallic luster.

9. Metallic Character (continued) Libretexts. “7.6: Metals, Nonmetals, and Metalloids.” Chemistry LibreTexts, Libretexts, 29 Aug. 2017, chem.libretexts.org/LibreTexts/University_of_Missouri/UM:_Chem_1320_(Keller)/07._Periodic_Properties_of_the_El ements/7.6:_Metals,_Nonmetals,_and_Metalloids. Trends for the Metallic character of an Element As one moves across a period in the periodic table one can observe that the metallic character decreases. This takes place due to the atom's ability to accept electrons so a valence shell would be fulfilled. The metallic character of elements increase as you move down the periodic table.The trend occurs as the electrons become easier to lose as the atomic radius increases. This increase in atomic radius decreases attraction between the nucleus who has a positive charge, and the electrons who have a negative charge, resulting in electrons to be held more loosely.

10. Power the Periodic Table Wields The periodic table holds great power as it can be utilized to predict the properties of various, even elements yet to be found. It shows that, groups and periods signal elements that share similar characteristics. The energy needed to remove an electron from a gaseous atom or ion through ionization energy. The periodic table also shows the measure of the size of an atom using ionic and atomic radius, and how likely an atom is to form a chemical bond by the trend of electronegativity. As well as the metallic character. All the four major trends in the periodic table contain concepts or ideas that tie in, or explain how each other trend works.