Dmitri Ivanovich Mendeleev, a Russian chemist, was the most important contributor for the early development of a periodic table of elements where in the elements were arranged on the basis of their fundamental property the atomic mass and also on the similarity of chemical properties. There were 63 elements known at his time. To classify these elements:
He then arranged 63 elements in the increasing order of their atomic masses and found that the elements with similar and chemical properties occur at regular intervals. He observed that elements with similar properties fall in the same vertical column. These vertical columns are called groups and horizontal rows of elements are called periods. On this basis, Mendeleev gave a periodic law, which states that “the properties of elements are a periodic function of their atomic masses”.
Which of the following are correct : (a) Mendeleev took the formulae of the hydrides and oxides formed by an element as one of the basic properties of an element for its classification. (b) Mendeleev examined the relationship between the atomic masses of the elements and their physical and chemical properties. | |||
Right Option : C | |||
View Explanation |
How many elements were known at the time of Mendeleev ? | |||
Right Option : A | |||
View Explanation |
Mendeleev examined the relationship between the ___________________________ of the elements and their physical and chemical properties. | |||
Right Option : B | |||
View Explanation |
My experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Abhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
I have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
It has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Being a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
It was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Abhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
My experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
A marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.