Short Answer

The modern periodic table was created by Dmitri Mendeleev, a Russian chemist. In 1869, he arranged the elements in increasing order of atomic mass and grouped them according to similar chemical properties. His arrangement helped predict the existence and properties of elements that were not yet discovered.

Later, Henry Moseley improved the periodic table by arranging the elements according to atomic number instead of atomic mass. However, Mendeleev is widely known as the “Father of the Modern Periodic Table” because of his original and highly accurate arrangement.

Detailed Explanation :

Creator of the Modern Periodic Table

The modern periodic table is one of the most significant achievements in chemistry. It organizes elements in a logical and systematic way, allowing scientists to understand their relationships, properties, and behaviour. The person who is most widely credited with creating the modern periodic table is Dmitri Mendeleev, a Russian chemist who developed the first workable and meaningful version of the table in 1869.

Mendeleev’s work transformed chemistry by providing a clear structure for elements, predicting new elements, and showing patterns in chemical behaviour. Although later improvements were made by Henry Moseley and others, Mendeleev remains the central figure in the creation of the periodic table.

Dmitri Mendeleev and His Contribution

Dmitri Mendeleev (1834–1907) was a Russian scientist known for his deep interest in the study of chemical elements. During the mid-1800s, chemists had discovered about 63 elements, but there was no organized way to classify them. Mendeleev believed that elements must follow a certain order based on their properties.

In 1869, he arranged the known elements in increasing order of atomic mass and placed elements with similar properties in the same columns. This arrangement formed the basis of the periodic table.

Why Mendeleev’s Table Was Revolutionary

Mendeleev’s table stood out because of three major achievements:

1. Logical Arrangement of Elements

He grouped elements with similar chemical and physical properties together, showing periodicity—repeating patterns in properties.

2. Prediction of New Elements

Mendeleev left blank spaces in his table for elements that were not yet discovered.
He even predicted the properties of these unknown elements.

For example:

• Eka-silicon → later discovered as Germanium
• Eka-aluminium → later discovered as Gallium
• Eka-boron → later discovered as Scandium

When these elements were later discovered, they matched Mendeleev’s predictions closely, proving the accuracy of his table.

3. Correction of Atomic Masses

Mendeleev adjusted some atomic masses that were incorrectly measured, based on how elements fit into his table. He prioritized chemical properties over incorrect data, showing his strong scientific intuition.

Limitations of Mendeleev’s Periodic Table

Although groundbreaking, his table had some limitations:

• Positions of some elements like cobalt and nickel were not entirely correct.
• Isotopes did not fit properly because they have the same chemical properties but different masses.
• Lanthanides and actinides could not be placed clearly.

These issues were later resolved by Henry Moseley.

Henry Moseley and Modern Improvements

In 1913, English physicist Henry Moseley discovered that the atomic number (number of protons), not atomic mass, was the correct basis for the periodic table.

He showed that:

Properties of elements depend on atomic number.

As a result:

• The modern periodic table is arranged by atomic number.
• Incorrect element positions were corrected.
• Isotopes were naturally grouped.

Because of this contribution, the periodic table used today is often called Moseley’s periodic table.

However, Mendeleev still receives primary credit because he created the first successful and predictive version.

Why Mendeleev is Called the Father of the Periodic Table

Mendeleev is known as the “Father of the Modern Periodic Table” because:

• He established the periodic law.
• He arranged elements in a meaningful pattern.
• He predicted new elements accurately.
• His table provided the foundation for the modern version.

His method helped chemists understand the patterns and relationships among elements for the first time.

Importance of the Modern Periodic Table

The periodic table is essential for modern chemistry because it helps:

• Predict properties of elements
• Study trends in chemical behaviour
• Understand valency and reactivity
• Classify metals, non-metals, and metalloids
• Find element groups and periods
• Learn electron configurations
• Identify family behaviour (alkali, alkaline earth, halogens, noble gases)

The work of Mendeleev and Moseley made the periodic table a powerful scientific tool.

Influence on Scientific Development

The periodic table influenced:

• Discovery of new elements
• Development of atomic theory
• Modern chemical bonding theories
• Understanding of periodic trends
• Growth of industrial and technological chemistry

It remains a central symbol of chemistry today.

Conclusion

The modern periodic table was created by Dmitri Mendeleev, who arranged elements according to their atomic masses and similar properties. His predictions of undiscovered elements made his table truly remarkable. Later, Henry Moseley improved it by arranging elements by atomic number, leading to the version used today. Mendeleev is honoured as the “Father of the Modern Periodic Table,” and his work remains one of the most important contributions to chemistry.