To review what we\'ve already learned about the periodic table as well as prepar

Question

To review what we've already learned about the periodic table as well as prepare us for our continued discussions on chemical bonding, we have given you a chapter written by Dmitri Mendeleev, the creator of the first version of the modern periodic table. Please read this chapter and answer the following questions: 1. One of the greatest achievements of Mendeleev's contributions to the periodic table were his predictions of properties for elements yet to be discovered at the time. On page 28 of the reading, he predicted "elements similar to Al and Si having atomic weights from 65-75." Since Mendeleev wrote these words, two elements have been found in this mass range. Name them. How are they similar to aluminum and silicon? 2. Mendeleev arranged elements according to their increasing atomic mass yet today we know that elements in the periodic table are arranged by increasing number of protons. Explain why either approach leads to the same periodic table (at least for the elements known at Mendeleev's time).

Explanation / Answer

1)eka aluminium as gallium

eka silicon as germanium

Silicon and Germanium. Solid state electronics arises from the unique properties of silicon and germanium, each of which has four valence electrons and which form crystal lattices in which substituted atoms (dopants) can dramatically change the electrical properties.

Gallium becomes a liquid at a low melting point of 29.8°C. It is a blue-gray metalthat can expand upon freezing. .. Gallium is useful as a semiconductor and has similar properties as aluminum.

b)Because atomic number is calculated on the basis of no of protons present in the atom

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