Difference Between Period vs Group

Difference Between Period vs Group

In 1868, Dmitri Mendeleyev, a Russian chemist and inventor, discovered the periodic table, the arrangement of chemical elements in a particular orientation. However, it has undergone many changes. To date, the table is still relevant within and outside the classroom. According to the table, elements are arranged in a certain pattern that distinguishes their characteristics from the rest.

Well, this classification is based on group and period. Today, many students often try to spot the difference between group and period, but they cannot do that. If you are one of them, worry no more. The reason is that in this informative guide, you will learn about their definitions, contrasts, and everything in between.

Definition of Period

A period is simply the horizontal arrangement of the elements in the periodic table. A close look at the elements that fall into this horizontal arrangement shows that they often have the same number of electron shells. By and large, the tableau contains about seven periods with electronegativity increasing from left to right through it.

While the first period has Helium and Hydrogen, the second has Lithium, Nitrogen, Oxygen, Neon, and others. Coming to the equality of atomic orbits, it is easy to notice that every element that made the first set has one orbital per electron.

In a similar vein, the second one has two orbitals per electron. As you progress through the orderly pattern, you will realize that the orbitals keep increasing. It is noteworthy that the size of the element drops across the columns because protons in the nucleus keep revving up.

Here, the constituents share the most significant unexcited electron energy level. It is not uncommon to see some periods have more constituents than others. The reason for this is the varying number of electrons per energy sublevel. To gain insight into the difference between period and group, a good understanding of the latter is critical.

Definition of Group

A group is a vertical or top-to-bottom organization of elements in the periodic table. A meticulous count of all the groups in the table shows that they are 18 in number. The constituents are metals, semi-metals, and non-metals. Because they exhibit similar properties, experts categorized them into families.

For instance, there is Group One, which is often referred to as the Lithium family. The members of this order are also called the Alkaline earth metals. As one moves across the line, each set has a name and similar properties. For example, the alkaline metals have a valence of two.

With respect to the elements, their sizes increase as one moves downward. The simplest explanation is that the nucleus commands the biggest number of protons and neutrons. While there have been several numbering methods in the past, the IUPAC (International Union of Pure and Applied Chemistry) came up with the most acceptable numbering system. This helps experts to properly number these vertically arranged elements.

Main Differences Between Period vs Group

Having come thus far, let us further simplify group vs period.

Basis of ComparisonPeriodGroup
MeaningThe horizontal column of constituents of the modern periodic tableThe vertical column of constituents of the modern periodic table
CharacteristicsThe elements do not have similar characteristicsThis category has similar characteristics, as seen in chemical and physical attributes
Striking semblanceThe members have the same number of electron composition  The members have the same number of valencies  
Total number7 periods in the modern periodic table18 groups are found in the modern periodic table
ElectronegativityA left-to-right movement shows an incrementA bottom-to-top movement shows an increment

Difference Between Period and Group: Conclusion

To summarize this period vs group guide, it is easy to infer that the former defines the horizontal order of elements in the periodic table while the latter sheds light on their vertical arrangement. While the table has undergone some changes over the years, it is still applicable to today’s study of elementary chemistry.

The features of elements that make it up are defined by period and group. With the table, it is very easy to understand how and why the elements share certain similarities. Finally, this guide has provided the essential distinctions that every student needs to know.