🧪 Chemistry · Classification of Elements and Periodicity in Properties · NEET & JEE

Mendeleev predicted the existence of undiscovered elements by leaving gaps. He called them by names like:

Answer: Eka-aluminium, Eka-silicon.

A Eka-aluminium, Eka-silicon
B Proto-metal in the majority of cases studied
C Pseudo-metals as widely reported
D Quasi-elements in standard practice

Correct answer: A. Eka-aluminium, Eka-silicon

Explanation: Mendeleev used the prefix 'eka-' (Sanskrit for 'one beyond') to name predicted undiscovered elements.

The complete modern periodic table showing all 118 elements with atomic number, symbol, and atomic mass, color-coded by element category

The complete modern periodic table (118 elements). Image: Cepheus et al., Public Domain, via Wikimedia Commons.

Concept context

The periodic table organises all 118 elements by atomic number and similar properties. Study periodic trends like atomic radius, ionization energy, and electronegativity, and learn how an element's position predicts its behaviour.

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Mendeleev predicted the existence of undiscovered elements by leaving gaps. He called them by names like:

Concept context

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