Advertisements
Advertisements
Question
In Mendeléev’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 58.71 amu. Give reason for the same.
Solution
In Mendeleev′s periodic table there are instances where elements with higher atomic masses are placed before the element with lower atomic mass. This was done to ensure that elements with similar properties were included in the same group. Hence Cobalt was placed before Nickel despite the higher atomic number of Cobalt than Nickel.
APPEARS IN
RELATED QUESTIONS
What are the main features of Mendeleev’s periodic table?
Write the merits of Mendeleev’s periodic table.
Use Mendeleev's Periodic Table to predict the formula of oxides of potassium, aluminum, and barium.
At the time of Mendeleev _______ elements were known.
Write the molecular formula of the oxide of any one of the elements in Mendeleev’s periodic table.
Distinguish between:
Mendeleev’s periodic table - Modern periodic table
What are the limitations of Mendeleev's periodic table?
On moving from left to right in a period in the periodic table, the size of the atom.
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.
