X Science Guess Paper Carbon and its compounds

Guess Paper  Class – X Subject - Science Carbon and its compounds

Section A – one mark each

1..Alcohols can be produced by the hydration of.

2. Write the name of C60 molecule.

3. The property of carbon to form a long chain in compounds is called ……………

4   Which of the following compounds have triple bond     C₂H₄, C₃H₄ and C₃H₆

5.    The general formula CnH2n for cyclo alkanes is the same as that of ………….

6. Write structure formula of 2- methyl propane.

7. The IUPAC name of acetylene is …………………

8. Name the functional groups present in the following compounds

CH₃COOH, CH₃COCH₂CH₃  

9.    ------and  ------are molecular formula of ethanol and propane.

10.  The IUPAC name of CH3CHO is ---------------

Section B – 2 marks each

11. Write the chemical equation of the reaction which takes place during burning of ethanol in air.

12. The molecular formula present in ester C₃H₇COOC₂H₅. Write the molecular formula of the alcohol and the acid from which it might be prepared.

13. A mixture of ethyne and oxygen is used for welding. Can you justify why a mixture of ethyne and air is not-used?

14. Write the reaction which is used as a test for ethanol and dehydration of ethanol.

15. What is reaction with ethanoic acid with ethanol?

                                             Section C – 3 marks each 

16.Write any three physical and chemical properties of ethanoic acid.

17. Write any three tests of carboxylic acids.

18. How many structural isomers are possible for pentane? Draw the structural formulae of all the possible isomers of pentane.

19. What are enzymes? Name the enzymes required for the fermentation of sugar cane to ethanol?

20. The formula of an ester is C3H7COOC2H5 write the formulae of the acid and alcohol from which the ester is prepared. 

Chapter wise test paper and Guess 

Posts Related to Chapter 10th Carbon and its Compounds        View/Study

X CBSE Study Accelerator E-Notes for Chapter Periodic Classification Of Elements

Classification of elements: the arrangement of elements in such a manner that elements with similar properties are grouped together while elements with dissimilar properties are separated.

EARLY ATTEMPTS OF CLASSIFICATION OF ELEMENTS

1. Lavoisier’s classification of elements: In 1789, Lavoisier first attempted to classify the elements into two divisions namely Metals and Non-metals. However this classification was not satisfactory as there were many exceptions in each category.

2. Dobereiner’s classification of elements: In 1817, Johann Wolfgang Dobereiner grouped three elements into what he termed triads.

In each case, the middle element has an atomic mass almost equal to the average atomic masses of the other two elements in the triad.

For example, elements like lithium, sodium and potassium have atomic masses 7, 23 and 39 respectively. They are grouped together into a triad as,

Li  (7)      Na  (23)     K      (39)

Here the atomic mass of sodium is the average of atomic masses of lithium and  potassium.

Limitation of Dobereiner’s law

Only three triads were identified from the element known at that time. Hence, this classification was not useful.

Newland’s law of octaves:

X Chemistry Test Paper For Ch - 5 Periodic Classification of Elements

1 mark questions:- 
 1. What is the name given to group of three similar elements by Dobereiner? 
 

2. State "Newlands law of Octaves" for classification of elements. 

3. Name the fundamental property used by Mendeleev as the basis of classification. 

 4. How many groups and periods are there in the Modern periodic table? 

 5. What was the prediction of Mendeleev regarding the gaps in his periodic table? 

 6. How is valency of an element determined? 

 7. What will be the valency of an element having atomic number 16? 

 8. How does valency vary in going down a group? 

 9. Why inert gases have zero valency? 

 10. What would be the valency of an atom containing 8 electrons in its outermost shell? 

 11. How does the electronegative character of elements vary along a period of the periodic table? 

 12. The present classification of elements is based on which fundamental property of elements? 

 13. Among first ten elements in the modern periodic table name the metals present. 

 14. Metals are on which side of Modern periodic table? 

 15. State Mendleev’s periodic law. 

 16. Name two elements, other than Gallium, whose existence was predicted by Mendeleev. 

 17. State Modern Periodic law. 

 18. Write the name given to the vertical columns in a periodic table. 

 19. What name is given to the horizontal rows in a periodic table? 

 20. Why do silicon is classified as Metalloid?

X CBSE Practice Work sheet

CBSE Board Questions

1. (a) What are metalloids ? Write any two examples.

 (b) Given below are some of the elements of first group Li, Na, K (Their atomic numbers are 3,11,19 respectively and they belong to 2nd 3rd and 4th period respectively) Arrange these in the decreasing order of metallic character exhibited by them. 

2. What are amphoteric oxides? Choose the amphoteric oxide from among the following

oxides :– Na2O, ZnO, Al2O3, CO2, H2O

3. Study the variation in the atomic radii of first group elements given below and arrange

them in increasing order :–

Group I element          Na       Li       Rb          Cs                  K

Atomic Radii P.M      86      152    244         262                 231

4. An element X has the electroic configuration as 2, 8, 7 :–

(a) What is the atomic number of the element?

(b) What will be the formula of its compound formed with Na?

(c) What is the name given to the family of this element?

5. How do you calculate the valence of the element from its electronic configuration? What is the valence of Mg with atomic number 12 and sulphur with atomic number 16? How does the valence vary in going down in a group?

6. Atomic radii of the elements of the period II are as follows:–

Period II elements :        Be         B      O      N     C       Li

Atomic Radius :           111        88     66     74    77     152

(i) Arrange them in decreasing order of their atomic radii.

(ii) How does the atomic size vary on moving from left to right in a period? Explain why?

(iii) How will the tendency to lose electrons will vary on moving from left to right in this period II?

7. Oxygen (O, 8) and sulphur (S, 16) belong to group 16 of the periodic table:-

(i) Write the electronic configuration and valence of these two elements?

(ii) Which among these will be more electronegative? Why?

8. Given below are the atomic radii of some elements of second period.

Element		B	O	N	C
Atomic Radius in pm	88	66	74	77

Arrange these elements in the increasing order of their atomic number . Give reason for your answer.

9. Two elements ‘A’ and ‘B’ belong to group 1 and 2 respectively in the same period.

Compare them with respect to :–

(a) Number of valence electrons.

(b) Valency

(c) Metallic character

(d) Size of atom

(e) Formulae of their oxides.

10. (a) Atomic radius of hydrogen is 37pm. Express it in meters. (b) How does atomic size vary in a group and in a period ?

11.  From the part of a periodic table, answer the following questions

1 Hydrogen	2	13	14 Carbon			15	16 Oxygen		17 Fluorine
X				P				Q
Y								R
Z								T

(a) Atomic number of oxygen is 8. What would be the atomic number of, Fluorine ?

(b) Out of ‘X’ and ‘Q’ which element has larger atomic size. Give reason for your answer Fluorine.

(c) Out of ‘Y’ and ‘Z’ which element has smaller atomic size. Give reason for your answer.

12.State Modern Periodic Law. Name the two elements of first period.

13.Two element X, Y and Z belong to 17th group but to 2nd,3rd and 4th period respectively. Number of valence electrons in Y is 7. Find the number of valence electrons in X and Z.

14. How does the metallic character of the elements vary (i) in a group (ii) in a period of the modern periodic table ?

15. Na, Mg, Al and P belong to 3rd period but are placed in first, second, thirteenth and fifteenth group. Number of shells occupied in Mg is three. What is the number of occupied shells in Na, Al and P. Give reason for your answer.

Q. What is the number of elements in first , second and third period of the periodic table? Give reason for your answer. 

X- chemistry Guess Test paper - Ch -5-Periodic-Classification-of-Elements

1. “Elements in Periodic Table show periodicity of properties” List any four such properties.

2. The following table shows the positions of six elements A, B, C,D,E and F in the modern periodic table

Group\Period	1	2		3to 12	13		14	15	16	17	18
2	A							B				C
3		D					E					F

(a). Which element will form only covalent compounds ?  

(b)  Which element is a metal with valency two ?

(c). Out of D and E , which one has a bigger atomic radius ? Give reason for your answers. 

3. (a) Atomic number of Mg and Al are 12 and 13 respectively. Write their electronic configuration. 
(b) Mention the period of the Modern Periodic Table to which the above two elements belong. Give reason for your answer

4. (a) State the Modern periodic law. (b) What is the total number of periods and groups in Modern Periodic Table
5. From the part of a periodic table, answer the following questions

1 Hydrogen	2	13	14 Carbon			15	16 Oxygen		17 Fluorine
X				P				Q
Y								R
Z								T

(a) Atomic number of oxygen is 8. What would be the atomic number of, Fluorine ?

(b) Out of ‘X’ and ‘Q’ which element has larger atomic size. Give reason for your answer Fluorine.

(c) Out of ‘Y’ and ‘Z’ which element has smaller atomic size. Give reason for your answer.

6. State two limitations of Newland's law of Octaves.

7. Name the scientist who proposed modern periodic law? On which fundamental property of elements it is based?
8. Why could no fixed position be given to hyderogen in Mendleev’s Periodic table?

9. What are metalloids? Give two examples.

10. In group 1 of periodic table three elements X, Y and Z have atomic radii 133pm , 95pm and 65pm respectively giving a reason, arrange them in the increasing order of their atomic number in the group.

11. In modern periodic table, the isotopes of Chlorine Cl-35 and Cl-37 having different atomic masses will be kept in different slots or they would be assigned same position on the basis of their chemical properties? Give reason in support of your answer.

12. Nitrogen (At no. 7) and Phosphorus (At no. 15) belong to group 15 of the periodic table:-

13. How and why does the atomic size vary as you go down a group?

14. Why was Dobereiner’s system of classification of elements into triads not found to be useful?

15.(a) “Silicon is classified as a metalloid.” Justify this classification.

(b) Name two more such metalloids.

(c) In which part of the Periodic Table we can look for metalloids. On which side of these we can get non- metals ?

Chemistry X | Carbon and its Compounds | Short type important questions

Q.1 Why is carbon tetravalent ?

Ans 1:Carbon atom has 4 electrons in the outermost shell.It needs 4 more electrons to complete its octet. Therefore , carbon is tetravalent .

Q.2 The formula of a hydrocarbon is Cn H2n. Name the family to which it belongs and also predict its nature.

Ans 2: The hydrocarbon belongs to alkenes It is unsaturated in nature .

Q.3 What is the valency of carbon in CH3-CH3, CH2=CH2 and HC=CH ?

Ans 3: The valency of carbon in all its compounds whether saturated or unsaturated is 4.

Q.4 Out of butter and ground nut oil , which is unsaturated in Nature?

Ans 4: Groundnut oil is unsaturated in nature .

Q.5 Why is high temperature not favourable for alcoholic fermentation?

Ans 5: The high temperature destroys the enzymes which are needed to carry fermentation .

Q.6 Name a cyclic unsaturated hydrocarbon, containing three double bonds?

Ans 6: Benzene

Q.7 What is the difference in the molecular mass of any two adjacent homologues?

Ans 7 : 14 mass units.

Q.8 Which has triple bond ; C2H4 ,C3H6 and C3H4 ?

Ans 8:C3H4 has triple bond in the formula .

Q.9 Which substance is added to denature ethyl alcohol?

Ans 9: A small amount of methyl alcohol , pyridine or copper sulphate is added to denature ethyl alcohol .

Q.10 Which ions are responsible for making water hard ?

Ans 10: Ca2+ and Mg2+ ions are responsible for making water hard.

Q.11 Name the catalyst commonly used in hydrogenation of oil to form fats?

Ans 11:Nickel.

Q.12 Write the name and molecular formula of alcohol derived from butane ?

Ans 12: C4H9OH Butanol

Q.13 Which gas is evolved when sodium carbonate or bicarbonate is added to ethanoic acid ?

Ans 13 : CO2 (carbon dioxide).

Q.14 What is SCUM ?

Ans 14: Scum is precipitate of Calcium and Magnesium salt of organic fatty acids.

Q.15 What are hydrophobic and hydrophilic parts in soaps?

Ans 15: The alkyl group(R) consisting of long chain of carbon atom is hydrophobic part while COONa group is hydrophilic in nature 

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CBSE X Periodic Classification of Elements Solved assignment

Periodic Classification of Elements Assignment Solved

Q1. Explain Dobereiner’s Law of triads along with an example .

Ans. Dobereiner tried to arrange elements with similar properties into groups of 3 elements each. He called these as triads. He showed that when the 3 elements into a triad were arranged in the order of increasing atomic masses, the atomic mass of the middle element was roughly the average of the masses of the other two elements. e.g.           Li                   Na                          K

atomic  mass                                     6.9                 23                          39

                                                         39+6.9/2  =    45.9/2   =    22.9   =  23

Q2. What were the limitations of Dobereiner’s Law of triads?

Ans. Dobereiner could identify only 3 triads from the element known at that time. Hence, this system is not useful.

Q3. State newland’s law of Octaves.

Ans. Newland arranged the elements in the increasing order of the atomic masses and found that every eight element had properties similar to that of the first like the notes of music.

Q4. What were the limitations of newland’s Law of Octaves?

Ans. 1. It was only applicable only up to Calcium as after Calcium every eighth element did  not posses , properties similar to that of first.

2. At a few places unlike elements were put together like cobalt and nickel along with F, Cl and Br.

Q5. Which 2 criteria did Mendeleev used to classify elements in his periodic table ?

Ans. Atomic mass and similarity in chemical property.

Q6. State Mendeleev’s periodic law.

Ans. Properties of elements are a periodic function of their atomic masses.

Q7. Why did Mendeleev leave gap in his periodic table?

Ans. Mendeleev place elements with similar properties one below the other leaving gap  for yet undiscovered elements.

Q8. Name the elements which have since been discovered that were left by Mendeleev  in his Periodic Table?

Ans. Eka Boron – Scandium             Eka   Al - Gallium         Eka   Si - Germanium

Q9. What are the limitations of Mendeleev's periodic table?

Ans. 
1. Position of Isotopes was not clear in his table.       

2. Wrong Order of atomic mass of certain elements  – Elements with higher atomic  mass were placed before elements having lower atomic mass.    e.g. Cobalt was placed before nickel.

3. Position of hydrogen was not clear in his periodic table.

Q10. What is Modern periodic Law ?

Ans. The Properties of elements are a periodic function of their atomic number.

Q11. How were the drawbacks of Mendeleev's periodic table resolved in the modern  periodic table?

Ans. As the modern periodic table was based on the atomic numbers so all the isotopes could be  placed together in one slot.  Secondly, the wrong order of atomic masses was also sorted as Cobalt's atomic number  was lower than Nickel even though it had a higher atomic mass.

Q12. How are the position of elements related to their atomic number in the Modern periodic table?

Ans. The number of valence electrons present in an atom of an element is equivalent to  the group number, while the total number of shells give the period number in which the element to present.

e.g 1. Atomic no. of Mg=12 ;  Electronic configuration=2,8,2     therefore, Gp. no.=2 or IIA   Period no.=3

e.g 2. Atomic no. of Cl=17;  Electronic Configuration=2,8,7       therefore, Gp. no.=17^th  or VIIA

Q13. Explain the gradation in properties of elements in the modern periodic table.

Ans. a. Valency: 

 Valency of elements remain the same  while going down a group 

 Moving across a   period, the valency of  elements increases   from 1 to 4 and then decreases till 0.

b. Atomic size or radius:

  It increases on going down a group

  It decreases in   Moving from left to right along a period.

c. Metallic and non-metallic  properties: :   Moving down a group of metals, metallic nature increases due to increasing size. However, in a group of non-metals the non-metallic character decreases on going    down

Going across a period, the metallic character decreases while Non-metallic character increases

Q14. Give examples of somea. Metalloids – Boron , Silicon , Germanium

b. Alkali metals – Sodium , lithium , Potassium

c. Halogens – Fluorine , Chlorine , Bromine

d. Alkaline Earth metals – Magnesium , Calcium

e. Nobel gases or Inert elements – Helium , Neon , Krypton