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प्रश्न
Which two elements show an ambiguity regarding their sequence in Mendeleev’s periodic table?
उत्तर
Cobalt (59Co) and nickel (59Ni) show an ambiguity regarding their sequence in Mendeleev’s periodic table.
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संबंधित प्रश्न
Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, Al, Si, Ba.
Name three elements that have a single electron in their outermost shells.
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?
Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?
State any three demerits of Mendeleev’s periodic table.
State whether the following statement is true of false:
According to Mendeleev's periodic law, the properties of elements are a periodic function of their atomic numbers.
What were the two criteria used by Mendeleev to classify the elements in his periodic table?
State Mendeleev's periodic law.
What chemical properties of elements were used by Mendeleev in creating his periodic table?
(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.
Why did Mendel choose garden pea for his experiments? Write two reasons.
Write a short note.
Mendeleev’s periodic law.
Write the merits of Mendeleev’s periodic table.
State Mendeleev's periodic law.
Use Mendeleev's Periodic Table to predict the formula of hydrides of carbon and silicon.
Why did Mendeleev's leave some gaps in his periodic table os elements? Explain your answer with an example.
Name an element whose properties were predicted on the basis of its position in Mendeleev's periodic table.
What are the demerits of Mendeleev’s periodic table?
What was the basis of Mendeleev's classification?
State the contributions made by Mendeleev towards the periodic table.
According to Mendeleev’s periodic law, properties of elements are periodic function of their _______.
At the time of Mendeleev _______ elements were known.
According to Mendeleev’s periodic law properties of elements are ______.
Write scientific reason.
There was no definitive place for isotope in Mendeleev’s periodic table.
On which basis Mendeleev organised periodic law?
What physical and chemical properties of elements did Mendeleev consider in compiling the periodic table?
In Mendeleev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the Periodic Table later?
Which of the following oxide is most basic?
Which of the following properties does not match the element of the halogen family?
The total number of electrons present in the first twenty elements of the periodic table is ______
Eka-aluminium and Eka-silicon are known as ______
In Mendeléev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later
Properties of the elements are given below. Where would you locate the following elements in the periodic table?
- A soft metal stored under kerosene
- An element with variable (more than one) valency stored under water.
- An element which is tetravalent and forms the basis of organic chemistry
- An element which is an inert gas with atomic number 2
- An element whose thin oxide layer is used to make other elements corrosion resistant by the process of “ anodising”
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?
State Mendeleev’s Law of Periodicity.
