Characteristics of Period and Group in Periodic Table

The group and period of an element in the periodic table determine its characteristics. This is the reason why studying the characteristics of the elements requires an understanding of the periodic table. In the periodic table, groups and periods each have unique characteristics.

Valency

The valence shell is the outermost shell of an atom. A valence electron is an electron that is found in an atom's valence shell. The electrical configuration of the parts changes as we proceed from left to right over time. The valency of elements varies even within a single period, despite the fact that the number of shells remains constant throughout time. The constant increase in valence electrons is to blame for this. As we go from group IA to VIIA and group 0, the valencies of the components in each group are 1, 2, 3, 4, 3, 2, 1, and 0 in that order. The quantity of valence electrons in an element determines its valency. A group's constituent parts all share the same valency. Group IA and VIIA elements have a valency of 1, whereas group IIA and VIA elements have a valency of 2. In a similar vein, group IIIA and VA components often have valency 3.

Atomic size

Elements' atomic sizes go smaller from left to right over time. While the number of shells stays constant, the number of protons and electrons rises as the atomic number increases. Thus, the same shell is filled with more electrons. In a similar vein, as the number of protons rises, so does the nucleus' positive charge and the force of attraction between the electrons in the shell and nucleus increases. Consequently, the atom contracts.As a result, the size of the atoms decreases throughout time from group 1 to 18. The separation between an atom's nucleus and valence shell defines its atomic size. For instance, sodium atoms contain K, L, and M shells, whereas lithium atoms only have K and L shells. Thus, in group IA, the size of the sodium atom is greater than that of the lithium atom.

Electropositivity and Electronegativity

Electropositivity is the ability of an element to shed its valence electrons and produce positive ions, or cations. Electronegativity is the ability of an element to acquire electrons in its valence shell to generate negative ions (fanions). Since an element's atomic size shrinks from left to right over time, its ability to lose electrons declines while its ability to receive electrons rises in tandem. As a result, from groups 1 to 18 of any period, an element's electropositivity, or metallic character, diminishes while its electronegativity, or nonmetallic character, grows.

Elevations in atomic size cause atoms at the top of a group to lose electrons more often than those at the bottom. Consequently, their nature of electropositivity also rises. Nevertheless, when they get farther away from the nucleus, their ability to acquire electrons diminishes. As a result, electronegativity drops across a group.

Chemical Reactivity

Metals exhibit decreasing chemical reactivity with time, while nonmetals exhibit increasing chemical reactivity over the same period. However, the element at a period's extreme right is inert. Let's examine the second period of the current periodic table, for instance:

As we can see, during the third phase, the atomic number rises from left to right. While the number of shells remains constant, the number of protons and electrons likewise grows correspondingly. The electrons inside the same shell continue to accumulate. The nucleus's attraction force increases as a result of an increase in protons within the nucleus. As a result, the nucleus attracts additional electrons from the shell. Atoms shrink as a result. Hence, of all the elements listed above, sodium has the biggest size. Furthermore, in the third era, sodium is the most electropositive or reactive metal. Chlorine is the most electronegative or reactive of them all, whereas argon is the smallest and an inert gas.

As one moves down the group, a metal's chemical reactivity rises while a non-metal's reactivity falls. Metals become more reactive as a result of elements losing their valence electrons more readily as they go further along a group. For instance, group IIA elements become more reactive in the sequence Be < Mg < Ca. As nonmetals get bigger, their propensity to acquire electrons decreases. Hence, nonmetals become less reactive chemically as a group. For instance, group VIA's nonmetals have a reactivity order of O > S > Se.