Modern Periodic Table: What is the Periodic Table?

Introduction

The periodic table is an arrangement of all the elements known to man in accordance with their increasing atomic number and repeated chemical properties. Elements are placed in specific groups in the table. A standard form of the table contains 18 groups (vertical columns) and 7 periods (horizontal rows). All elements of the periodic table are represented in their respective groups and periods. The periodic table is one of the most iconic and recognizable tools in the study of Chemistry. It has been around for over 150 years. The periodic table, in general terms, is the arrangement of chemical elements. So, these elements with similar properties can be grouped together. 

What is the Periodic Table? Why is Periodic Table Made?

Periodic table- It is a scheme of all known elements to man arranged in terms of their atomic number in increasing order and terms of repetitive chemical properties. They are grouped in table form whereby a row corresponds to a period and a column to a group. The elements are organized in a left to right and top to bottom way depending on their atomic numbers. Thus,

• Elements in the same group will have the same valence electron configuration and hence, similar chemical properties.
• Whereas, elements in the same period will have an increasing order of valence electrons. Therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases.
• Naturally occurring elements are the 94 elements of the periodic table, and the other elements between 95 and 118 were only produced in laboratories or nuclear reactors. The periodic table that we are currently using is a new and better variant of some of the models proposed by scientists during the 19th and 20th centuries. Dimitri Mendeleev proposed his periodic table in line with the discoveries made by a number of scientists prior to him, such as John Newlands and Antoine-Laurent de Lavoisier. But Mendeleev is credited with the credit for his periodic table formulation.

Some Key Characteristics of Groups in the Periodic Table

• The modern periodic table has nine groups and they are indicated by roman numerals including I, II, III, IV, V, VI, VII, VIII and zero.
• The zero group is put in inert gases or the noble gases.
• The group number is equal to the valency of the element in the group.
• The normal elements are the elements of the groups that mimic the typical elements. The elements of IA, IIA, IIIA, IVA, VA, VIA and VIIA are normal elements, for example.
• These elements of the groups which are not similar to the typical elements are known as transition elements. As an example, transition elements include IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIIIB group elements. Both in IA and VIIA groups hydrogen is placed.
• The periodic table consists of a total of 18 different groups. These are as follows:

Group 1: Alkali metals group (hydrogen not included)
Group 2: Alkaline earth metals group
Group 3-12: Transition and Inner transition metals group 
Group 13: Boron group
Group 14: Carbon group 
Group 15: Nitrogen group
Group 16: Oxygen group 
Group 17: Halogen group 
Group 18: Noble gases group

• Few groups are named by taking the reference of the first element of the group. Example: Carbon family, Boron family, etc.
• Atomic weight, atomic size, electropositive character, and metallic character of elements increase down the group.
• Ionization potential, electron affinity, and electronegativity of elements decrease down the group.

Groups of the Periodic Table

Group 1: Alkali Metals

Group 1 are the alkali metals. It is a group of 6 elements. This is the group that includes Lithium (Li) to Francium (Fr). They are called alkali metals since whenever they react with water they produce compounds known as alkalies (i.e. hydroxide compound of these elements). As an example, potassium hydroxide and sodium hydroxide.

Few Characteristics of Group 1

• Less dense than other metals.
• One loosely bound valence electron.
• Highly reactive, with reactivity increasing moving down the group.
• The largest atomic radius of elements in their period.
• Low ionization energy.
• Low electronegativity.

Group 2: Alkaline Earth Metals

Alkaline Earth Metals, including magnesium, calcium, and barium, are slightly less reactive than alkali metals but still form basic oxides. They are commonly found in minerals, are used in construction (like cement), and are essential in biological processes, such as calcium in bones and magnesium in chlorophyll.

Few Characteristics of Group 2

• Two electrons in the valence shell.
• Readily form divalent cations.
• Low electron affinity.
• Low electronegativity.

Groups 3-12: Transition Metals

The d-block elements, also called the transition elements, are located in the middle of the periodic table. It spans from Titanium (Ti) through Copernicium (Cn). The transition metal group consists of 38 elements in the Periodic Table.

Group 13: Boron Group

The Boron Group includes elements like boron, aluminum, and gallium. These elements have three valence electrons and show a variety of properties, from the metallic nature of aluminum to the metalloid behavior of boron. They are used in electronics, construction, and in manufacturing specialized materials.

Group 14: Carbon Group

The carbon group is a periodic table group consisting of carbon, silicon, germanium, tin, lead, and flerovium. This group lies in the p-block of the periodic table. The members of this group have four valence electrons in their outermost shell. As all the elements in group 14 have 4 electrons in the outermost shell, the valency of group 14 elements is 4. They use these electrons in the bond formation in order to obtain an octet configuration.

Group 15: Nitrogen Group

The Nitrogen Group, containing The first two elements in the group, nitrogen (N) and phosphorus (P) are nonmetals; the remaining three elements are arsenic (As), antimony (Sb), and bismuth (Bi). Nitrogen is crucial for life, forming proteins, while phosphorus is key for energy transfer in cells. The elements in this group vary from nonmetals to metals and have vital biological and industrial uses.

Group 16: Chalcogens

Chalcogens include oxygen (O), sulphur (S), selenium (Se), tellurium (Te), and polonium (Po). These elements have six valence electrons and form acidic oxides. Oxygen is essential for life, while sulfur is widely used in industrial processes like the production of sulfuric acid. The group plays a key role in environmental and biological systems.

Group 17: Halogens

Halogens (such as fluorine, chlorine and Iodine) are nonmetals that include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). They easily react with metals to form salts and are applied in disinfectants, pharmaceuticals and other chemicals. In the treatment of water and manufacture of plastics, fluorine and chlorine are vital.

Group 18: Noble Gases

The inert gases, including helium, neon, argon, krypton, xenon, and radon, possess complete outer electron shells. They are not reactive and hence they are typically used in lighting, refrigeration and even in medical use. Although these gases are nonreactive, they are useful in industrial and scientific reactions.

Conclusion

The Periodic Table is an essential tool in understanding the properties and relationships between elements. Its arrangement based on atomic numbers and periodic chemical properties allows us to predict behaviors and trends across different groups and periods. Each group in the table, such as the alkali metals, halogens, and noble gases, exhibits unique characteristics that govern their reactivity, bonding, and applications. From the highly reactive alkali metals to the inert noble gases, the table reflects the complexity of chemical behavior and provides a roadmap for scientific discovery and practical applications. Understanding the Periodic Table is fundamental in chemistry, providing insights into how elements interact, bond, and form compounds crucial for life, industry, and technology.