Beginner Topic 1095 of 1102 Biochemistry, Environment & Industry

Mendeleev

Created the periodic table and predicted missing elements.

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In-depth explanation of Mendeleev

Dmitri Mendeleev published his periodic table in 1869, arranging the known elements by increasing atomic weight and grouping them by similar chemical properties. He left gaps for elements he predicted would be discovered, and he described their likely properties, such as density and atomic weight. The discovery of gallium in 1875, scandium in 1879 and germanium in 1886 confirmed many of his predictions. The modern table is arranged by atomic number rather than atomic weight, which resolved some anomalies. The periodic law is one of the foundations of chemistry. Mendeleev's table remains one of the most important syntheses in the history of science.

Going deeper: Mendeleev

Key ideas: Arranged 63 known elements in 1869 by increasing atomic mass and recurring properties, leaving gaps and predicting eka-aluminium (gallium, found 1875), eka-silicon (germanium, 1886) and eka-boron (scandium). Swapped some pairs (Te and I) to fit chemical behavior. Moseley (1913) showed atomic number is the true basis, giving the modern periodic law.

Common mistakes and connections: Mistake: saying the modern table orders by atomic mass; it orders by atomic number. Meyer arrived at a similar table independently. Mendeleev did not predict noble gases, which were added as group 18 later. Links to periodic trends, atomic structure and predictive power of theories.

Visualization of Mendeleev

Mendeleev predicted the density of the missing element eka-silicon as 5.5, close to the 5.32 later measured for germanium. The interactive lesson shows this as a live animation or chart.

Worked example and use case

Mendeleev predicted eka-silicon, which was later discovered as germanium with a density close to his estimate.

Frequently asked questions about Mendeleev

What is Mendeleev?

Created the periodic table and predicted missing elements.

Is Mendeleev a beginner, intermediate or advanced topic?

Mendeleev is a beginner topic in Biochemistry, Environment & Industry. It needs no earlier chemistry lessons and is a good starting point.

What should I learn before Mendeleev?

Study these earlier topics in Biochemistry, Environment & Industry first: History of Chemistry, Alchemy, Lavoisier.

What comes after Mendeleev?

The next topics in Biochemistry, Environment & Industry are Marie Curie and Nobel Prize in Chemistry.

Can I practise Mendeleev with quizzes?

Yes. The interactive lesson includes a self-check question on Mendeleev, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Mendeleev fits in Biochemistry, Environment & Industry

Mendeleev is topic 120 of 127 in Biochemistry, Environment & Industry.