Question

three elements p, q,r have atomic numbers 2,13 ,18
which of these belong to the same period?
which of these belong to the same group?
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Answer 1

Answer:

Education is a platform in which young generations are trained and make them future-ready. Education provides knowledge and skills which help the person to be employable. The Indian education system is very popular and diversified among other countries’ education systems due to its change in the evolution from ancient to the modern education system. During the ancient and medieval periods of education, students were trained by teachers in such a manner that they can survive and live in that era. After independence, there is a tremendous growth in the Indian education system providing teaching and training in all aspects, but it does not satisfy the global demands of the market. This chapter focuses on teaching methodology, curriculum, characteristics, methods of learning, aims of the Indian education system during the ancient and medieval period and how it differed in today’s modern education and what are the things that our today’s modern education need to learn and implement from ancient and medieval education. The mentioned points are used to differentiate ancient, medieval, and modern education with advantages and disadvantages. Through this chapter, students, teachers will get to know the difference in the education system and what else to be adapted in the future to overcome all the problems.

Explanation:

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Answer 2

Answer:

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Periodic Classification of Elements:--

Matter around us is present in the form of elements, compounds and mixtures.

Elements are substances containing atoms of only one type eg. Na, Mg, Au etc.

There are 118 elements known to us. All these have different properties.

Out of these 118, only 98 are naturally occurring.

NEED FOR PERIODIC CLASSIFICATION:--

Elements were classified so that they could be studied easily and in an organised manner. The earliest attempt to classify the elements resulted in grouping the then known elements as metals and non-metals. Later further classifications were tried out as our knowledge of elements and their properties increased.

DOBEREINER's TRAIDS :-

In the year 1817, Dobereiner, a German chemist, tried to arrange the elements with similar properties into groups. When elements were arranged in the order of increasing atomic masses, groups of three elements (known as triads), having similar chemical properties were obtained. The atomic masses of the middle element of the triad was roughly the average of the atomic masses of the other two elements.

NEWLAND'S LAW OF OCTAVES :-

Newland arranged the then known elements in the order of increasing atomic masses and found that the properties of every 8th element is similar to that of the 1st element. He compared this to the octaves found in music and called it the 'Law of Octaves'. For example, the properties of lithium (Li) and sodium (Na) were found to be the same.