Ionization Energy
Ionization energy is the quantity of energy that an isolated, gaseous atom in the ground electronic state must absorb to discharge an electron, resulting in a cation.
In a chemical reaction, ionization energy is the key to wether various atoms make covalent or ionic bonds with each other. Elements with big difference in ionization energy will make ionic bonds. This usually applies to when metals and non-metals react with each other. On the other hand, elements that reside close to each other in the periodic table or elements that do not have much of a difference in ionization energy make covalent bonds. For example, when metals reacts with metals and when non-metals react with non-metals.
Generally, The lower the ionization energy is, the more readily the atom becomes a cation. Therefore, the higher this energy is, the more unlikely it is the atom becomes a cation. Elements on the right side of the periodic table have a higher ionization energy because their valence shell is nearly filled. Elements on the left side of the periodic table have low ionization energies because of their willingness to lose electrons and become cations. Thus, ionization energy increases from left to right on the periodic table.
Atomic Radius
Atomic radius is the total distance from an atom’s nucleus to the outermost orbital of electron. It’s like the radius of a circle, where the centre of the circle is the nucleus and the outer edge of the circle is the outermost orbital.
Atomic size gradually decreases from left to right across the periodic table. The reason behind is, within a period or family of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged. The effect of increasing proton number is greater than that of the increasing electron number; therefore, there is a greater nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom’s shell closer to the nucleus. The valence electrons are held closer towards the nucleus of the atom. As a result, the atomic radius decreases.
Moreover, down the periodic table, atomic radius increases. The valence electrons occupy higher levels due to the increasing quantum number (n). As a result, the valence electrons are further away from the nucleus as ‘n’ increases.
Chemical Reactivity
Chemical reactivity is the tendency of a substance to undergo chemical reaction, either by itself or with other materials and to release energy.
In metals, reactivity increases as you go down a group in the periodic table, 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. Moreover, in metals, reactivity decreases as you go across a periodic table to the right, as they still want to give away valence electrons and they have more of them to get rid of, which requires more energy. In this case, Fluorine is the most reactive element, which a stream of fluorine gas will ignite a concrete block at room temperature. On the other hand, the least reactive metal will be platinum, which cannot be oxidized in air, even at high temperatures.
Ion Charge
Ionic charge is the electrical charge of an ion, created by the gain (negative charge) or loss (positive charge) of one or more electrons from an atom or group of atoms.
In many cases, elements that belong to the same group on the periodic table form ions with the same charge because they have the same number of valence electrons. Thus, the periodic table becomes a tool for remembering the charges on many ions. For example, all ions made from alkali metals, the first column on the periodic table, have a 1+ charge. Ions made from alkaline earth metals, the second group on the periodic table, have a 2+ charge. On the other side of the periodic table, the next-to-last column, the halogens, form ions having a 1− charge.
Conductivity
Conductivity refers to the ability of a material to transmit energy. There are different types of conductivity, including electrical, thermal, and acoustical conductivity. The most electrically conductive element is silver, followed by copper and gold. Silver also has the highest thermal conductivity of any element and the highest light reflectance. Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance. Because silver tarnishes, it is less desirable for high frequencies because the exterior surface becomes less conductive.
As to why silver is the best conductor, the answer is that its electrons are freer to move than those of the other elements. This has to do with its valence and crystal structure.
Most metals conduct electricity. Other elements with high electrical conductivity, are aluminum, zinc, nickel, iron, and platinum. Brass and bronze are electrically conductive alloys, rather than elements.
Periodic Table 