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R J
Subject: Science
, asked on 6/3/18
8-3 pls third one
8. निम्नलिखित प्रश्नों के संक्षिप्त में उत्तर लिखिए-
(क) 'बालगोबिन भगत की मौत उन्हीं के अनुरूप हुई' कथन को सोदहारण स्पष्ट कीजिये।
(ख) "मानवीय करुणा की दिव्य चमक" शीर्षक की सार्थकता पर प्रकाश डालिए।
(ग) काशी मेें अभी भी क्या शेष बचा हुआ है?
Answer
1
R J
Subject: Science
, asked on 6/3/18
Q. Answer the question in the image:
Answer
1
Yash Chavan
Subject: Science
, asked on 5/3/18
how to find group number of an element if valency is given
Answer
4
Raghav Singh
Subject: Science
, asked on 3/3/18
Till what point we must know elements with atomic numbers? I know till 20 , as after 20 we get different configurations . Please tell me , I am scared as there is a question in NCERT in which we have to write the configuration of element 38. The configuration of elements after 20 is different.
Answer
2
Raghav Singh
Subject: Science
, asked on 2/3/18
Q. If the 3rd shell can have 18 electrons why we have 4th shell in the configurations of these elements?
Answer
2
Raghav Singh
Subject: Science
, asked on 2/3/18
Q).
Why the configuration of these elements is written in this way? like 2,8,18,9,2 in yttrium why not 2,8,18,8,3?
Answer
1
Raghav Singh
Subject: Science
, asked on 2/3/18
Why deep sea is blue?
Answer
1
Raghav Singh
Subject: Science
, asked on 2/3/18
Please answer question 31, is it the haber's process?
Q.31. A non-metal A which is the largest constituent of air combines with hydrogen on heating in presence of Fe (as catalyst) and forms a gas B. When this gas B is treated with
H
2
S
O
4
, compound C is formed which is broadly used as chemical fertiliser.
(i) Identify A, B and C.
(ii) Locate the position of A in the modern periodic table.
(iii) Which elements are present before and after the element A ?
(iv) Write the electronic configuration of element A.
Answer
1
Raghav Singh
Subject: Science
, asked on 2/3/18
Q. In the modern periodic table, calcium (atomic number = 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium? Explain configuration of 38. From which point this type of configuration starts ? What is the maximum no. of electrons a shell can acquire at this point?
Answer
2
Raghav Singh
Subject: Science
, asked on 2/3/18
In question 25 look at the last part, why the formula of compound is XZ? Valency of X is 3 and Z is 2, by crossing we get X2Z3, then why
Q.25. Three elements X, Y and Z have atomic numbers 7, 8 and 9 respectively.
(i) State their positions (group number and period number both) in the modern periodic table.
(ii) Arrange these elements in the decreasing order of their atomic radii.
(iii) Write the formula of the compound formed when X combines with Z.
Answer
2
Raghav Singh
Subject: Science
, asked on 2/3/18
In question 27 , it is asked to find the element which is a metalloid . Now there are about 7 metalloids , if any of the metalloids is asked what will i do ? I mean till which point the elements with atomic numbers must be memorised? I know till 20.
Q.27. Consider the part of periodic table given below and answer the following questions.
(i) The atom of which element is smaller in size e or h?
(ii) Which element is the most electropositive in nature?
(iii) Which element has only one proton in its atom?
(iv) What is the valency of g?
(v) How many valence electrons does g have?
(vi) Name the element which is a metalloid.
Answer
2
Raghav Singh
Subject: Science
, asked on 2/3/18
Please answer question 37 with explanation, i have the answer but it is not widely explained . Please explain it.
Q.37. A salt when dissolved in water dissociates into cations and anions as follows:
If both the ions consist same number of electrons and the molecular weight of salt is 74.5. Then identify the position of A and B in the periodic table.
Answer
1
Raghav Singh
Subject: Science
, asked on 2/3/18
Q. How do the following changes occur on moving from top to bottom in d group?
Effective nuclear charge experienced by valence electrons. What is
Z
e
f
f
?
Answer
1
Raghav Singh
Subject: Science
, asked on 1/3/18
Why groups have two names, like group 17 is called VA(five a) why?Is there any order ?
Answer
3
Raghav Singh
Subject: Science
, asked on 1/3/18
How to memorise mendeleev's table? I need it to do qiestions based on oxides and hydrides.
Answer
1
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8. निम्नलिखित प्रश्नों के संक्षिप्त में उत्तर लिखिए-
(क) 'बालगोबिन भगत की मौत उन्हीं के अनुरूप हुई' कथन को सोदहारण स्पष्ट कीजिये।
(ख) "मानवीय करुणा की दिव्य चमक" शीर्षक की सार्थकता पर प्रकाश डालिए।
(ग) काशी मेें अभी भी क्या शेष बचा हुआ है?
Q. Answer the question in the image:
Q.31. A non-metal A which is the largest constituent of air combines with hydrogen on heating in presence of Fe (as catalyst) and forms a gas B. When this gas B is treated with , compound C is formed which is broadly used as chemical fertiliser.
(i) Identify A, B and C.
(ii) Locate the position of A in the modern periodic table.
(iii) Which elements are present before and after the element A ?
(iv) Write the electronic configuration of element A.
Q. In the modern periodic table, calcium (atomic number = 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium? Explain configuration of 38. From which point this type of configuration starts ? What is the maximum no. of electrons a shell can acquire at this point?
Q.25. Three elements X, Y and Z have atomic numbers 7, 8 and 9 respectively.
(i) State their positions (group number and period number both) in the modern periodic table.
(ii) Arrange these elements in the decreasing order of their atomic radii.
(iii) Write the formula of the compound formed when X combines with Z.
Q.27. Consider the part of periodic table given below and answer the following questions.
(i) The atom of which element is smaller in size e or h?
(ii) Which element is the most electropositive in nature?
(iii) Which element has only one proton in its atom?
(iv) What is the valency of g?
(v) How many valence electrons does g have?
(vi) Name the element which is a metalloid.
Q.37. A salt when dissolved in water dissociates into cations and anions as follows:
If both the ions consist same number of electrons and the molecular weight of salt is 74.5. Then identify the position of A and B in the periodic table.
Q. How do the following changes occur on moving from top to bottom in d group?
Effective nuclear charge experienced by valence electrons. What is ?