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Making Order out of Chaos - The Modern Periodic Table

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Who Proposed Modern Periodic Law: An Introduction

Physicist Henry Moseley first gave the idea of the Modern Periodic Table in 1913. He demonstrated that every element's identity is solely defined by atomic mass (the number of protons or electrons). He made a revelation that exposed the real origins of the periodic table. Based on atomic masses, Mendeleev created the first periodic table.


In the Modern Periodic Table, the elements are grouped into seven horizontal rows (periods) and eighteen vertical columns in the order of their atomic numbers (groups). Since their valence electrical configurations are similar, the elements in the same group exhibit related chemical characteristics. The periodic table is separated into s-block, p-block, d-block, and f-block elements based on their electronic configuration.


What is the Modern Periodic Table?

The properties of the elements can be related to one another using the periodic table, and the properties of new elements that have not yet been discovered or created can be predicted. The modern periodic table is crucial to understanding Chemistry. According to their individual atomic numbers, elements are arranged in ascending order in the modern periodic table.

There are 18 vertical columns called groups and seven horizontal rows called periods. Since all of the elements in a group have the same number of outer electrons, they exhibit comparable physical and chemical characteristics. However, as we proceed from top to bottom in a group, they demonstrate a steady change.


Moving from left to right, the elements in a period exhibit a steady change in attributes. As we move from left to right, atomic size increasingly shrinks. Compared to the 63 elements in Mendeleev's periodic table, the current periodic table has more elements. It currently contains 118 components. Without the modern periodic table, the study of the chemistry of elements would not have been conceivable.


The classification of the elements is far simpler. The first two groups on the left side of the periodic table, which are made up of highly reactive elements, are the principal classification of elements in the current periodic table (except hydrogen).


The other groups are transition metals that are located in the middle of the periodic table and mostly exhibit the characteristics of metals. First group elements have one electron in their valence shell, while second-group elements have two electrons. Groups 3 through 12 of the periodic table's elements are classified as transition metals. At the bottom of the periodic table, several metals are arranged separately in two rows. Actinides and Lanthanides are the names for these substances.


Non-metals and metalloids come on the right side of the periodic table, metalloids typically occur in a diagonal line. These substances are referred to as metalloids because they have characteristics of both metals and non-metals. Noble gases are located on the extreme right of the table. They belong to the 18th group, and their valence shells are fully filled. They are known as inert or noble gases and are non-reactive.


Difference Between Mendeleev and the Modern Periodic Table

The modern periodic table is different from Mendeleev’s periodic table in certain aspects that are listed below-

Features

Mendeleev Periodic Table

Modern Periodic Table

Principle

Based on atomic mass.

Based on atomic number.

Classification

The classification will be based on the hydride and oxide chemical formulae.

The classification will rely on the electronic configuration of elements.

Inclusion of Noble Elements

Not included

Included


Organization of Elements

Some elements with heavier atomic masses are listed before those with lighter ones in this periodic table.

The elements are organised according to the sequence of increasing atomic number and atomic mass.

Number of Elements

Contain 63 elements

Have 118 elements


Key Features

  • The atomic number of the elements, a fundamental feature, forms the foundation of the modern periodic table.

  • The table makes a clear connection between the element's location and electronic configuration. The modern periodic table is simple to recall and duplicate.

  • Sodium, which is an alkali metal group chemical element, is soft enough to be cut with a knife.

  • The transition elements are arranged in a separate block in the modern periodic table.

  • Noble gases are classified as a separate group called group-18 in the modern periodic table.

  • A level of uniformity is maintained in the modern periodic table.

  • The light metals comprise groups 1 and 2, while the zero group elements are present in group 18 in the modern periodic table.

Last updated date: 21st Sep 2023
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FAQs on Making Order out of Chaos - The Modern Periodic Table

1. What do you mean by atomic mass?

It is the measure of mass of one single atom of an element. It is roughly equivalent to the mass number or to the average number that takes into account the relative abundances of various isotopes.

2. What is the atomic number?

It is defined as the number of protons of an atom that is contained in the nucleus. The number of electrons in a neutral atom is also called the atomic number.

3. What are transition elements?

The group of metallic elements that make up a central block in the periodic table, such as iron, manganese, and copper. Chemically, they exhibit varying valancy, and a variety of colored molecules.