NCERT Solutions
Board Paper Solutions
Ask & Answer
School Talk
Login
GET APP
Login
Create Account
Popular
Latest
Expert Answers
ALL
Son Ser
Subject: Science
, asked on 28/2/18
Arrange → Li, Be, F, N
–
in increasing order of atomic radii
Answer
6
Deisha Gupta
Subject: Science
, asked on 27/2/18
How were the anolamlies of Mendeleev classification made into order in the modern periodic table ?
Answer
2
Simran
Subject: Science
, asked on 24/2/18
Elements be,mg and ca each having 2 valance electrons in their valance shellsare in periods 2 ,3 and 4 respectively.which one of them is least reactive and why..! Pls and fast...
Answer
2
Steve
Subject: Science
, asked on 23/2/18
Ca Sr Ba is dobereiners triad write its chemical property
Answer
2
R J
Subject: Science
, asked on 23/2/18
2 and 3
Q.(ii) Draw ray diagrams to show the principal focus of a :
(a) Concave mirror
(b) Convex mirror
(iii) Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.
State the type of the mirror M and one characteristic property of the image Q.
Answer
2
Romil Singh
Subject: Science
, asked on 23/2/18
three elements x y z have atomic number 7 8 9 respectively .Aarrange these elements in the decreasing order of their atomic radii
Answer
3
Ananya Joshi
Subject: Science
, asked on 22/2/18
Question 9
Answer
5
R J
Subject: Science
, asked on 22/2/18
16
Answer
5
Romil Singh
Subject: Science
, asked on 20/2/18
what were the two criteria used by Mendeleev in creating his periodic table
Answer
3
Nirlipta Padhy
Subject: Science
, asked on 20/2/18
Atoms are neutral , why and how do they still lose electrons?
Answer
2
Atharva Patil
Subject: Science
, asked on 18/2/18
write the IUPAC Name ch3ch2oh.
Answer
3
Atharva Patil
Subject: Science
, asked on 18/2/18
write the IUPAC Name ch3ch2ch2br
Answer
6
Mahdi Reza Vakil
Subject: Science
, asked on 18/2/18
Sodium has atomic number 11. Configuration is 2,8, 1. Has 1 valence electrons, hence placed in group 1.
Potassium has atomic number 12. Configuration is 2,8,2. Has 2 valence electrons, hence placed in group 2.
Aluminium has atomic number 13. Configuration is 2,8,3. Has 3 valence electrons, hence should be placed in group 3. But it is placed in group 13.( 10 added ). WHY?.
Why 10 added to group number in 2nd and 3rd period and not in 4th to 7th period in Modern Periodic Table. Pls, explain.
Answer
1
R J
Subject: Science
, asked on 17/2/18
Explain why though both plane mirror and sheet of paper is reflecting surface but we see our face in mirror not in sheet of paper why
Answer
2
R J
Subject: Science
, asked on 16/2/18
Q. Can you run electric geysor with power rating 2kW. 220 V on a 5 A line? Give reason to justify your answer.
Answer
3
Prev
1
2
3
4
5
Next
What are you looking for?
Q.(ii) Draw ray diagrams to show the principal focus of a :
(a) Concave mirror
(b) Convex mirror
(iii) Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.
State the type of the mirror M and one characteristic property of the image Q.
Potassium has atomic number 12. Configuration is 2,8,2. Has 2 valence electrons, hence placed in group 2.
Aluminium has atomic number 13. Configuration is 2,8,3. Has 3 valence electrons, hence should be placed in group 3. But it is placed in group 13.( 10 added ). WHY?.
Why 10 added to group number in 2nd and 3rd period and not in 4th to 7th period in Modern Periodic Table. Pls, explain.