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Sanitya Srivastava
Subject: Science
, asked on 15/2/18
Write the electron configuration of RB and SR fast
Answer
1
U
Subject: Science
, asked on 13/2/18
Q.4. The atomic number of helium is 2, but it is not placed in second group. Explain why?
Answer
2
U
Subject: Science
, asked on 13/2/18
plzz ans it.
Answer
3
R J
Subject: Science
, asked on 13/2/18
Wriye down the combustion of saturated and unsaturated hydrocarbon
Answer
1
Bhavyaa Trehan
Subject: Science
, asked on 12/2/18
Pls help me with the. Give. Reason. Part
Answer
2
Medha Bhattacharya
Subject: Science
, asked on 12/2/18
Someone plz ans this question
Q.(i) Four students were asked to test the pH of four samples as shown under. Whose result is reported correctly?
(ii) Bottle A contains a dilute solution of vinegar and bottle B contains sodium carbonate solution. Write the colour seen in pH paper dipped in A and B.
Answer
3
Medha Bhattacharya
Subject: Science
, asked on 12/2/18
Someone plz ans this question
Q. Lithium (Li), sodium (Na) and potassium (K) were put in the same group on the basis of similar properties.
(i) What is the similarity in their properties?
(ii) If atomic weights of lithium and potassium are 7 and 39 respectively, what is the atomic weight of sodium?
Answer
3
Medha Bhattacharya
Subject: Science
, asked on 12/2/18
Someone plz ans question
Q. Metallic and non-metallic character varies on moving from left to right in a period. Explain.
Answer
1
Medha Bhattacharya
Subject: Science
, asked on 12/2/18
Someone plz ans this question
Answer
2
Champ Jee
Subject: Science
, asked on 10/2/18
Give the number of elements in 2nd and 5th period of periodic table. Is there any method to recognise the no. Of elements in a period?
Answer
4
Champ Jee
Subject: Science
, asked on 9/2/18
Study the variation in the atomic radii of first group elements given below:
(i) Arrange the elements in the increasing order of their atomic numbers.
(ii) Name the elements which have the smallest and largest number of atoms.
(iii) How does the metallic nature vary as one goes down a group?
(iv) How many valence electrons are there in each element?
(v) Write the reaction of sodium with water.
Answer
1
Champ Jee
Subject: Science
, asked on 9/2/18
Q6. What is periodicity in properties of element with reference to the Modern Periodic Table? Why do all the elements of the same group have similar properties ? How does the tendency of elements to gain electrons change as we move from left to right in a period ? State the reason of this change.
Answer
2
Medha Bhattacharya
Subject: Science
, asked on 9/2/18
Solve this :
6. An element Y has a total of three shells, with six electrons in its valence shell.
i. What will be the atomic number of this element ?
ii. In which period will you find this element ?
iii. Name another element which belongs to the same group as this element.
iv. Identify the preceding and the following elements in the same period.
v. State the formula of its oxide and chloride.
Answer
3
Medha Bhattacharya
Subject: Science
, asked on 9/2/18
Someome plz ans this
Q.2. Compare the arrangement of elements in Mendeleev's Periodic table and Modern Periodic Table.
(any three)
Answer
1
Medha Bhattacharya
Subject: Science
, asked on 9/2/18
Someone plz ans this.
Q.1. An element 'X' has mass number 27 and the number of neutrons is 14. Identify the group number and period of 'X'.
Answer
1
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Q.(i) Four students were asked to test the pH of four samples as shown under. Whose result is reported correctly?
(ii) Bottle A contains a dilute solution of vinegar and bottle B contains sodium carbonate solution. Write the colour seen in pH paper dipped in A and B.
Q. Lithium (Li), sodium (Na) and potassium (K) were put in the same group on the basis of similar properties.
(i) What is the similarity in their properties?
(ii) If atomic weights of lithium and potassium are 7 and 39 respectively, what is the atomic weight of sodium?
Q. Metallic and non-metallic character varies on moving from left to right in a period. Explain.
(i) Arrange the elements in the increasing order of their atomic numbers.
(ii) Name the elements which have the smallest and largest number of atoms.
(iii) How does the metallic nature vary as one goes down a group?
(iv) How many valence electrons are there in each element?
(v) Write the reaction of sodium with water.
6. An element Y has a total of three shells, with six electrons in its valence shell.
i. What will be the atomic number of this element ?
ii. In which period will you find this element ?
iii. Name another element which belongs to the same group as this element.
iv. Identify the preceding and the following elements in the same period.
v. State the formula of its oxide and chloride.
Q.2. Compare the arrangement of elements in Mendeleev's Periodic table and Modern Periodic Table. (any three)
Q.1. An element 'X' has mass number 27 and the number of neutrons is 14. Identify the group number and period of 'X'.