Elements: Classification of Elements

The periodic properties of atoms are related to the fact that the elements present in the periodic table are arranged in the sequence of growing and increasing atomic numbers. All the elements in the periodic table show different trends. Moreover, we can take the help of periodic law and table formation to predict their atomic, chemical, and physical properties.

Periodic Properties of Elements

Atomic Size

The atomic radius of an atom can never be determined as there is never a zero chance of finding an electron and a distinct boundary to the atom. All that can be measured is the gap between two nuclei, known as the internuclear distance. One-half of the distance between the nuclei of two similar atoms is a covalent radius. At the same time, an ionic radius is one-half the distance amid the nuclei of two ions of an ionic bond.

For example, a distance of 74 pm is in 2 hydrogen atoms in an H2 molecule. Hence, the hydrogen atom’s atomic radius is ‘742 = 37 pm 74 2 = 37 pm’.

The distance should be reserved for the tinier cation and the bigger anion. Furthermore, a metallic radius is one-half the distance amid the nuclei of two atoms adjacent to each other in a crystalline structure. However, the noble gases are not considered in the trends in atomic radii due to the extreme level of debate and doubts on the experimental values of their atomic radii. In addition, the SI units used for the measurement of the atomic radii are; the nanometer (nm) and the picometer (pm).

Metallic Character

The metallic character helps define the chemical properties represented by the metallic elements. Usually, the metals tend to drop the electrons for producing cations. Moreover, the non-metals tend to have more electrons for producing anions. They are high in oxidation potential, and that’s why they can be oxidised effortlessly and are strong reducing agents. The metals also produce basic oxides, where the basicity of the oxide is directly proportional to the metallic character. Some examples of elements with metallic characters are; silver, gold, iron, copper, etc.

While moving from the left to the right side across the table, the metallic character reduces; it happens because the elements accept the electrons easily for filling up their valence shells, so these elements take on forming ion’s non-metallic character. When going up the table, the metallic character reduces because of the massive pull that the nucleus has on the electrons present outside. It becomes difficult for the atoms to lose electrons and produce cations due to the pull.

Non-metallic Character

The non-metals tend to get more electrons in the chemical reactions and have a high level of attraction for the electrons in a compound. The most reactive non-metals are present in the upper right part of the periodic table. Moreover, noble gases are considered an exceptional and extraordinary group because they lack reactivity. Still, the most reactive non-metal is fluorine, and it is not present in nature as a free element. Some examples of elements with metallic character are; chlorine, oxygen, etc.

Notably, no clear division exists among the non-metallic and metallic characters. While moving across the periodic table, there is a rising tendency to accept the electrons (non-metallic) and reduce the chances of an atom giving up one or more than that electron (metallic).

Ionisation Energy

Ionisation energy or ionisation potential are the same things with the same meaning. It is the total energy required for separating an electron and a molecule or an isolated atom from each other. Every successive electron being separated has some amount of ionisation energy. Moreover, a chemical element expressed in electron volts or joules has an ionisation potential generally measured in an electric discharge tube. An electric current generates a rapidly moving electron that collides with a gaseous atom. It results in the ejection of one of its electrons.

For example, when sodium and chlorine combine for making salt, the sodium atom gives up an electron that leads to a positive charge. In contrast, chlorine gets the electron and turns negatively charged.

Electron Affinity

The electron affinity is defined as the amount of energy liberated while adding an electron to a neutral atom to form a negatively charged ion. Moreover, it is tough and challenging to measure the electron affinities of atoms. Therefore, the values are present for just a few chemical elements, mainly halogens. For example, when a fluorine atom is in the gaseous form and gets an electron to make F⁻(g), the energy change will be = “-328 kJ/mol”.

Conclusion

The classification of elements – periodic properties of atoms study material concludes that the periodic table has various and multiple elements that have different and unique properties, capabilities, and characteristics at the same time. The periodicity of elements is briefly explained in the article. Moreover, it also tells that the ionisation energy, electron affinity, etc. are different and dissimilar for all the periodic table elements.