At the time of Mendeleev, the number of elements known was
63
65
62
64

Academic Chemistry NCERT Class 10

Correct Answer: (a) 63

Explanation: In Mendeleev’s periodic table, elements were placed based on the atomic mass, and chemical properties. At the time of Mendeleev, the number of elements known was only 63.

Tutorialspoint

Updated on: 10-Oct-2022

36 Views

In the classification of the then known elements, Mendeleev was guided by two factors. What are those two factors?
Give an account of the process adopted by Mendeleev ′ for the classification of elements. How did he arrive at “Periodic Law”?
Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.
Mendeleev ′ predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.(a) Name the elements which have taken the place of these elements(b) Mention the group and the period of these elements in the Modern Periodic Table.(c) Classify these elements as metals, non-metals or metalloids(d) How many valence electrons are present in each one of them?
What is the time of the day just before sunrise known as?
Find the number of spectators standing in the stadium at time t in Python
Mendeleev predicted the existence of certain elements not known at that time and named two of them as eka-aluminium, and eka-silicon.(a) Name the element which has taken the place of (i) eka-aluminium, and (ii) eka-silicon (b) Mention the period/periods of these elements in the modern periodic table. (c) Write the group/ groups of these elements in the modern periodic table. (d) Classify these elements as metals, non-metals or metalloids. (e) How many valence electrons are present in the atoms of each of these elements?
Program to return number of smaller elements at right of the given list in Python
Rate of change in velocity with respect to the time is known as ________
C++ code to number of standing spectators at time t
Sort Elements on the basis of the Number of Factors
How to identify multiple elements at the same time in Selenium with python?
The three elements predicted by Mendeleev from the gaps in his periodic table were known as eka-boron, eka – aluminium and eka-silicon. What names were given to these elements when they were discovered later on?
Get the number of elements of the Masked Array in Numpy
Find the arrangement of queue at given time in C++

Kickstart Your Career

Get certified by completing the course

Get Started

Advertisements