CBSE Important Questions

Q. 1. What are Newland octaves. Give its drawbacks.

Q. 2. What are differences between Mendleev’s and modern periodic tables?

Q. 3. How many elements are there in 1st period?

Q. 4. Name two elements which shows chemical charecteritics similar to mg?

Q. 5. What are defects of Mendleev’s periodic table?

Q. 6. On which factors the size of atoms depend? Explain?

Q. 7. How the following changes in period?

1. Metallic charecterics
2. valency
3. Electron affinity
4. Atomic radii

Q. 8. An element A with atomic no.14 and another B of atomic no. 17. Which one has :

1. more metallic character
2. greater atomic size .
   name one element having similar characteristics as element A and one as B.

Q. 9. Which among Cl, F,Br.and Iodine has

1. largest atomic size
2. highest reactivity

Q. 10. Why noble gasses are inert?

Q. 11. Scandium,Gallium and germanium are discovered later but Mendeleev,s left gaps for them.What name he gave these elements

Q. 12. What special names given to group 1 ,2, 17 & 18

Q. 13. Observe following table and answer following questions

Q. 13. Observe following table and answer following questions

1. State whether A is metal or non metal
2. which is more reactive ? A or C.
3. Will C be larger or smaller in size than B
4. which type of ion,cation or anion will be formed by A?

Q. 14. elements X of atomic no. 12 and 13 , are taken. Give there group and period no. on basis modern table. Name:-

1. three elements having 1 valence electron
2. two elements having +ve valency 2
3. Lithium , sodium ,potassium are metals that react with water to give hydrogen. What are similarity among atoms of these metals?

Q. 15. Which element has

1. two shells,both of which are completely filled
2. the electronic configuration is 2, 8, 7(c)

Q. 16.

1. Which element form only covalent compounds.
2. which element is a metal with valency 2.
3. which element is nonmetal with valency of 3.
4. out of D and E which one has a bigger atomic radius why?
5. write a common name for the family of element C and F?