Case Study Questions Class 10 Science Chapter 5 Periodic Classification of Elements
CBSE Class 10 Case Study Questions Science Periodic Classification of Elements. Important Case Study Questions for Class 10 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Periodic Classification of Elements.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Based Questions Class 10 Science Chemistry Chapter 5
CASE STUDY : 1
In 1866, John Newlands, an English scientist, arranged the then known elements in the order of increasing atomic masses. He started with the element having the lowest atomic mass (hydrogen) and ended at thorium which was the 56th element. He found that every eighth element had properties similar to that of the first. He compared this to the octaves found in music. Therefore, he called it the ‘Law of Octaves’. It is known as ‘Newlands’ Law of Octaves’.
i) The Newlands of octaves, was applicable only upto……..
Ans: Calcium
Reason: After calcium every eighth element did not possess properties similar to that of the first.
ii) What was the assumptions regarding the discovery of elements?
Ans: Only 56 elements exist in nature and no more elements would be discovered in future.
iii) What were the drawbacks of newlands while putting the element into same slot?
Ans: Cobalt and nickel arr in the same slot and in the same column with chlorine and fluorine. Also, he placed Iron far away from cobalt and nickel which they resembles most of the properties.
iv) Does Newlands law of octaves and Dobereiner have some same classification?
Ans: Yes, both had placed the sodium and lithium in same slot.
v) What was the limitations of Newland law of octaves regarding the weight of elements in the classification?
Ans: Newland law of octaves worked well with lighter elements.
CASE STUDY : 2
The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’. Let us see what decides the placing of an element in a certain group and period.
Look at the group 1 of the Modern Periodic Table, and name the elements present in it.
Write down the electronic configuration of the first three elements of group 1.
What similarity do you find in their electronic configurations?
How many valence electrons are present in these three elements?
You will find that all these elements contain the same number of valence electrons. Similarly, you will find that the elements present in any one group have the same number of valence electrons.
i) Write the electronic configuration of atomic no. 19. Identify the element.
Ans : 19- 2, 8, 8, 1
Element: Potassium
ii) What is the another name of group 17?
Ans: Halogens
iii) Name some elements of group number 18?
Ans: Helium, Neon, Argon, Krypton
iv) Which group contains oxygen and sulphur?
Ans: Both the elements comes under group 16.
v) Name some elements which are called as alkali metals?
Ans: Lithium, sodium, potassium.
CASE STUDY : 3
The metals like Na and Mg are towards the left-hand side of the Periodic Table while the non-metals like sulphur and chlorine are found on the right-hand side. In the middle, we have silicon, which is classified as a semi-metal or metalloid because it exhibits some properties of both metals and non-metals
i) Which block contains alkali and alkaline earth metals?
Ans: The S- block i.e group 1 & 2.
ii) Name some of the metalloids or semi- metals in the periodic table?
Ans: Boron, silicon, germanium, arsenic.
iii) Name some metals and non- metals in the periodic table?
Ans- Metals- lithium, Beryllium, Magnesium, Sodium
Non-metals- Carbon, Nitrogen, oxygen, fluorine
iv) How many groups and periods are there in periodic table?
Ans- 18 groups and 7 periods
v) Write the electronic configuration of the following elements:
a) Nitrogen b) Chlorine
Ans: a) N – 2, 5
b) Cl- 2, 8, 7
CASE STUDY : 4
The term atomic size refers to the radius of an atom. The atomic size may be visualised as the distance between the centre of the nucleus and the outermost shell of an isolated atom. The atomic radius of hydrogen atom is 37 pm (picometre, 1 pm = 10–12m).
i) What is the trend of atomic size when moving from left to right?
Ans: The atomic size decreases in moving from left to right due to an increase in nuclear charge.
ii) Arrange the following atom in increasing order of their atomic size: B, Be, O, N, Li, C
Ans: O < N < C < B < Be < Li
iii) Why does the atomic size increases down the group?
Ans: As new shells are added as we go down the group. This increases the distance between the outermost electrons and the nucleus, so atomic size increase instead of increase in nuclear charge.
iv) Which of the elements has greater atomic size: Li or K?
Ans: Potassium has larger atomic size than lithium as going down the group atomic size increases and lithium comes in period 2 and potassium is in period 4.
v) Metals are electropositive or electronegative in nature?
Ans: They are electropositive in nature because they lose electrons while forming the bonds.
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