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प्रश्न
Mendeléev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.
- Name the elements which have taken the place of these elements
- Mention the group and the period of these elements in the Modern Periodic Table.
- Classify these elements as metals, non-metals or metalloids
- How many valence electrons are present in each one of them?
उत्तर
- Eka-Silicon was replaced by germanium, Eka-aluminium was replaced by gallium in the Mendeleev's periodic table.
- Germanium-group number 14 and 4th period.
Gallium-group number 13 and 4th period. - Germanium is a metalloid and gallium is a metal.
- Germanium has 4 electrons and gallium has 3 valence electrons.
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संबंधित प्रश्न
Name two elements that have two electrons in their outermost shells.
Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?
By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?
(a) Write its electronic configuration and determine its valency.
(b) Is it more reactive or less reactive than Ca (atomic number 20)? Justify your answer giving reason.
(c) Is it a metal or a non-metal?
(d) Write the formula of its oxide.
Mendeleev's contributions to the concept of a periodic table laid the foundation for the Modern Periodic Table. Give reasons.
Why did Mendeleev's leave some gaps in his periodic table os elements? Explain your answer with an example.
How did Mendeleev's arrangement of elements correlate with the periodicity of the properties of elements?
While designing the periodic table, Mendeleev considered the chemical and physical properties of the elements.
The properties of eka-aluminum predicted by Mendeleev are the same as the properties of a later discovered elements: ______
Eka-aluminium and Eka-silicon are known as ______
