Class 10th Ch-5 Ncert Questions Answer Periodic Table, This is the first chapter in your Inorganic Compound. From this chapter the major topic of chemistry that is Inorganic Chemistry starts.
This is a very Basic and Easy chapter of Inorganic Compound. Each and Every time in Board exams 1 five Marks Question Asked. So from the Examination point of view, this chapter is very important.
In this chapter, we are going to cover the following topics in depth:- Ancient Methods of classifying the elements, History of the periodic table, properties of the different elements, Ways to classify the elements, How to put the elements in the different slots.
How the properties of the different elements change when we move across the period and down the group. So let’s get started with our topic. Here is the table of content given below through which you can navigate Easily.
Page No. 81 Class 10th Ch-5 Ncert Questions Answer
Q1. Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
Ans:- Yes, Döbereiner’s triads also exist in the column of the Newlands’ octaves. Because if you’ll compare the 2nd Group of the Newlands’ periodic table you will find that li, Na,k are in the similarly arranged which also follows the formula of Döbereiner’s triads.
Q2. What were the limitations of Döbereiner’s classification?
Ans:- 1. This law was applicable for very few elements.
2. Only a few elements work and fit in the periodic table.
3. The Formula and the rules given in this law were not able to classify all the elements.
Q3. What were the limitations of Newlands’ Law of Octaves?
Ans:- 1. The Periodic Law of Newlands was only applicable to Calcium.
2. He predicts that only 56 elements will be discovered in the future.
3. He placed some of the elements in the wrong order. Like he placed Iron very far to Nikel and cobalt.
4. He also put more than 1 element in one slot.
5. There was no place for the noble gases in the Newlands Periodic table.
Page no. 85 Class 10th Ch-5 Ncert Questions Answer
1. Use Mendeléev’s Periodic Table to predict the formulae for the oxides of the following elements: K, C, AI, Si, Ba.
Ans:- Oxygen belongs to the 16th group and the Electronic Configuration of oxygen is 2.8.6. Means the no. of electrons present in the last she’ll be 6, and to complete its octet it will gain 2 electrons.
Therefore the valency of Oxygen will be 2.
Now, (1). When K reacts with the Oxygen it will form K2O, because K belongs to the 1st group with valency 1.
(2). When Carbon[C] reacts with the Oxygen it will form CO2 [carbon dioxide], Because carbon belongs to the 14th group with 4 electrons in its outermost shell. So you have studied in chapter 4 that carbon share Electrons and it will make bonds with the Oxygen to form CO2.
(3). When Aluminium reacts with Oxygen then it will form Al2O3. Because the Al has the 3 Electrons in its outermost shell.
. When [Silicon] Si reacts with the Oxygen it will form SiO2. Because like carbon it also belongs to the 14th group. So it will show the same property as Carbon.
. When Ba reacts with the O2 it will form Barium Oxide [BaO]. Because it belongs to the 2nd group with the valency of 2.
Q2. Besides gallium, which other elements have since been discovered that were left by Mendeléev in his Periodic Table? (any two)
Ans:- Germanium and Scandium.
Q3. What were the criteria used by Mendeléev in creating his Periodic Table?
Ans:- Mendeléev considers the following points at the time of Creating Periodic table.
- Oxygen and Hydrogen are the most reactive elements in nature. So he takes Oxygen and Hydrogen as a base.
- His table was completely based on arranging the Elements in Increasing Atomic Mass.
Q4. Why do you think the noble gases are placed in a separate group?
Ans:- Noble Metals should be placed in a separate group because they don’t show any Property like Loosing or gaining of the electrons. They are very Stable and Inert in nature. They are not like all other elements of the Periodic table. That’s why they kept in the Separate group that is the 18th group also known as the Zero group.
Page no. 90 Class 10th Ch-5 Ncert Questions Answer
Q1. How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?
Ans:- In modern Periodic Table all the elements are arranged according to their Atomic no. So this removes all the flows related to the Atomic masses.
2. The atomic number of cobalt is 27 and the nickel is 28. Hence cobalt will come before nickel even though its atomic mass is greater. Here this main problem fixed.
3. The Isotopes problems also fixed. Because the isotopes have the same atomic number but different atomic masses so when it kept at the same position.
Q2. Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
Ans:- Ba and Ca show similar properties to the Magnesium. Because Ca and Ba also belongs to the 2nd group in the periodic table.
And Member of the same group shows similar properties. Also Be, Sr and Ra will show a similar property to the Magnesium. Because all these elements belong to the 2 groups in the Periodic Table.
Ans:- Li, K, Na are the three electrons which have the single electrons on their outermost shell. Because they belong to the 1st group in the periodic table and have 1 electron in their outermost shell.
2. Calcium and the Magnesium have the 2 electrons in their outermost shell because they belong to the 2nd group in the periodic table. And all the elements present in the 2nd group have the 2 electrons in their outermost shell.
3. Ne, Ar, He has a completely filled outermost shell. Because they belong to zero groups or from the 18th group. And elements of these groups are completely filled with the electrons. And these elements are very inert in nature.
Ans:- . Yes, All these elements have the 1 electron in their outermost electron shell. And also all these elements belong to the first group of the periodic table. that’s why all these 3 elements show similar chemical and physical properties.
. These elements have their completed outermost shell. These gases are very inert and non-reactive in nature and these gases do not react with any other element.
These gases belong to the same group that is the 18th group.
Q5. In the Modern Periodic Table, which are the metals among the first ten elements?
Ans:- H, He li, Be, B, C, N, O, F Ne. These are the first 10 elements that are present in the periodic table. out of these, Li, Be, B are the Metals, Whereas H is undefined, N, O, and F are the non-metals and He and Ne are the noble gases.
Ans:- In this case, Ga(Gallium) is more Metallic than all of the given elements in the question above. Because out of this Gallium is bigger in size and it will lose its electrons faster than the other ones. So that’s why Ga is more metallic in this case.
Page no. 91 [Back Exercise] Class 10th Ch-5 Ncert Questions Answer
Ans:- (c). The atoms lose their electrons are easy, this statement is worn here in this case.
Because when we move from left to right in the periodic table then the non-metallic properties of the elements Increase and hence the property of losing electrons get reduce because of the decrease in the size of the atom of the element.
Ans:- In this case, (c) Mg will be the correct answer.
Ans:- (a). Neon is the element in the 18th group that have the 2 shells and the shells are completely filled.
(b). Magnesium has the electronic configuration of 2, 8, 2.
(c). Silicon has the 3 total shells and has 4 electrons in its outermost shell. Electronic Configuration of Silicon is 2, 8,4.
(d). B is the answer because the electronic configuration of carbon is 2,3.
Ans:- All elements that lie to the same column that is 13 group shows a similar property like boron. All the elements of this period have the same no. of electrons in their valance shell.
Although Boron is a non-metal, all other elements present in the 13 groups are metals.
Ans:- (i). The atomic no. of the given element above in the Question is 17 Because the no. of electrons present in an atom is equal to its atomic number.
(ii). The atom of which the electronic Configuration will be similar to the 2,8,7 will be similar. This means if the in its outermost shell the electron will be 7 then the element will be chemically similar. Here the answer is F(Florine).
- Element A is a non-metal in this case.
- Here Element C is less reactive than Element A.
- The size of C is smaller than B
- A will form an anion.
Ans:- The Electronic Configuration of Nitrogen will be 2,5. The no. of electrons that will present in the outermost shell of the Nitrogen will be 5. That is why the valency will be 3.
Similarly, The electronic configuration of the Phosphorus will be 2,8,7. and that is why the valency of the phosphorus will also be 3.
(ii). Nitrogen will be more electronegative in nature as compared with the Phosphorus Because of the following reasons:-
- On moving down the group the no. of shells increased. That makes the outermost shell electrons more away from the nucleus.
- This is the reason that causes a decrease in the tendency of electron attraction.
Q8. How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
Ans:- The no. of valence electrons tell the position of any element in the modern periodic table. And electronic configuration tells the valence electrons. And an atomic number of the atom tells the electronic configuration.
So, ultimately Atomic no. of the atoms decides their position in the modern periodic table.
Ans:- The electronic configuration of calcium is 2,8,8,2. Thus, calcium has 2 valence electrons. The electronic configuration of the element having atomic number 12 that is Magnesium is 2, 8.2. Thus, this element with 2 valence electrons will show similar properties like Calcium.
Q10. Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.
|Mendeleev’s Periodic Table||Modern Periodic Table|
|The elements in this periodic table are arranged in Increasing Atomic Mass||The elements in this periodic table are arranged in increasing order of their Atomic number.|
|There are 8 groups in this periodic table.||There are 18 groups in the modern periodic table.|
|Each group is subdivided into subgroup ‘a’ and ‘b’, that is oxide and hydride.||Groups are not subdivided into sub-groups further.|
|There was no group for the noble gases earlier. It was discovered when the noble gases were found.||A separate group is meant for noble gases.|
|There was no place for isotopes And this was a big flow for this periodic table.||There is not any specific problem for Isotopes. Because the elements are arranged in increasing order of atomic number.|
Now here the NCERT Question answers of this chapter ends. Hopefully, this content was helpful for you. If you have any doubts related to this chapter then please let me know in the comment section.
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