The nuclear charge of Li is:
Which of the following is one of the major drawbacks of Mendeleev's periodic table?
With an increase in temperature by 10k ,the rate of reaction becomes double. How many times the rate of reaction will be, if the temperature is increased from 303 k to 353 k ?
Name the element that first shows some visible metallic properties at room temperature.
The properties of_________were predicted by Mendeleev before their isolation.
The number of elements known in Mendeleev's presented periodic table is:
The law of triads is not applicable to:
Lanthanides belong to which period?
The elements in the_______group have________chemical properties.
All the elements of a group have similar chemical properties because they have same number of valence electrons in their outemost shell
In Mendeleev's periodic table,the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93 amu was placed before nickel having an atomic mass of 58.69 amu.Reason for the same is that:
The law of triads was given by:
In the year 1829, Johann Wolfgang Dobereiner,a German scientist, was the first to classify elements into groups based on John Dalton's assertions. He grouped the elements with similar chemical properties into clusters of three called 'Triads'. The distinctive feature of a triad was the atomic mass of the middle element.When elements were arranged inorder of their increasing atomic mass,the atomic mass of the middle element was approximately the arithmetic mean of the other two elements of the triad.
In order to fit elements into his table, Newlands adjusted two elements in the same slot, but also put some unlike elements in the same slot.
For example, cobalt and nickel were in the same slot and these were placed in the same column as fluorine, chlorine and bromine which have very different properties than these elements. Iron,which resembles cobalt and nickel in properties,had been placed far away from these elements.
Mendeleev examined the relationship between_________and______for classification of elements.
Pair of element shaving same number of valence electrons is:
How many periods were there in Mendeleev's periodic table?
What were the limitations of Mendeleev's periodic table?
Law of Triad was proposed by
Which of the following statements can help a chemistry student to predict chemical properties of an element?
(I) Position of element in the periodic table
(II) Atomic number of the element
(III) Number of shells in the atom
(IV) Number of electrons in the outermost shell.
If the two members of a Dobereiner triad are phosphorus and antimony, the third member of this triad is:
_________were not included in Mendeleev's periodic table.
Whose name is not associated with the development of periodic Table