Education Science

Difference Between Period and Group

Difference Between Period and Group

The periodic table of chemistry is something that students are expected to remember assiduously without ever understanding why they are being required to study it in the first place. For some, it’s just a subject matter that is covered in their course curriculum. This small periodic table, on the other hand, is much more essential than that; it is a road map that opens up a universe of possibilities for scientists and researchers all around the globe.

The periodic table was created by Dmitri Mendeleyev, who was born in Russia. Many others came before him and made valiant efforts to organize the chemical components in various configurations. However, Dmitri’s conclusion was widely recognized around the globe.

Specifically, in scientific acronyms, the rows are referred to as Periods, while the columns are referred to as Groups.

Period Vs. Group

The most significant distinction between Periods and Groups is their organization on the periodic table; Periods are placed in a horizontal fashion, whilst Groups are grouped in a vertical manner on the periodic chart.

Mendeleyev left a few rows unfilled throughout the process of organizing the components with the hope that further elements will be added in the near future, which proved to be correct. Gallium, to many people’s surprise, was one of the elements that could fill in the blanks.

What is a Period?

On the periodic table, a period is a horizontal row that runs from the far left to the far right of the column. There are now seven periods on the periodic table, as of today. When a new basic energy level adds up with the electrons, a new period is said to have begun. Every element in a period is expected to have the same number of atomic orbitals as the other elements in the period.

For example, every element in the first period has just one orbital for its own electrons, but every element in the second period has two orbitals for its own electrons. Similarly, as you travel down the row, the number of orbitals continues to grow.

The size of the element reduces as you go through a period because the number of electron shells stays constant throughout the period, but the number of protons in the nucleus increases as you progress through the period. This is the reason why the atom becomes heavier as its size continues to shrink.

When you look at the periodic table, you will see that various elements are included inside each row.

The first period has just two items (1 and 18), the second and third periods each include eight elements, the fourth and fifth periods each contain 18 elements, and finally, the sixth and seventh periods each contain 32 elements.

What is a Group?

When you count the groups in the periodic table from the top to the bottom, there are a total of 18 groups. Names are assigned to each group, and each group has its own name.

Among the groupings are metals and nonmetals as well as semi-metals, which are organized into families owing to their similarities in physical and chemical characteristics. For example, Group 1 is a member of the Lithium family, which is classed as Alkene metals. In a similar vein, each group in the lane is designated with a family name.

Elements of the related group share characteristics with one another because they have the same number of electrons in their outermost shell. As you proceed down any group, the size of the element grows in proportion to the group below it. This is due to the fact that the nucleus contains a huge number of protons and neutrons. On top of that, the atom has an additional electron shell, which increases the weight of the atom.

There are two alternative approaches to illustrating the aspects for groups to consider. Being familiar with both the numbering system and the periodic table is necessary since the periodic table occurs in both of these configurations.

In the United States, they utilized the letters A and B to denote each element in the group, but it was discovered to be a disordered numbering system, which was problematic.

The International Union of Pure and Applied Chemistry (IUPAC) came up with the notion of numbering the elements as (1,2, 3,… 18) in order to minimize any potential mistake. Both of the numbering schemes, on the other hand, are acceptable. However, IUPAC’s numbering scheme seems to be straightforward and well-organized.

Difference Between Period and Group

  • Position: In the periodic table, groups are located in the upright column, while periods are located in the straight rows.
  • The number of groups and periods in the periodic table: There are a total of 18 groups and 7 periods in the periodic table, with the groupings being classified into distinct metal kinds and families.
  • Chemical characteristics: All of the elements in the group have chemical or physical qualities that are comparable to one another, while periods have the same electron hierarchy as one another.
  • As we go along the group, starting at the top and working our way down from there, we see a rise in electron energy levels. The electron’s energy level, on the other hand, stays constant during each time of observation.
  • Electronegativity: This decreases from the top to the bottom of a group and increases from the left to the right of a time period. While studying the periodic table, it is crucial to keep this in mind as well.


In the contemporary periodic table, groups and periods are the two ways in which the chemically organic or inorganic elements or metals are classified, with the primary distinction between groups and periods being the placement of the element of metal in the periodic table. In this lesson, you learned that periods are located on the horizontal line, and groups are located on the vertical line.

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