Mendeleev's propdicted the properties of ________unknown elements.

Options

A. seven
B. two
C. five
D. three

Answer

D

Explanation

Scandium, gallium, and germanium discovered later had properties similar to `eka`-born, `eka`-aluminium, and `eka`-silicon, respectivelty, as predicted by Mendeleev. It is important to remember that Mendeleev's periodic table was devised more than `50` years before the discovery and characterization of subatomic particles.