AP SSC 10th Class Physical Science Chapter 9 Solution – Classification of Elements – The Periodic Table

AP SSC 10th Class Physical Science Chapter 9 Solution – Classification of Elements – The Periodic Table

Andhra Pradesh SSC 10th Class Physical Science Chapter 9 Classification of Elements – The Periodic Table Solution for AP SSC 10th Class Physics/Chemistry Exam. Lots of Students of Andhra Pradesh Board will search on internet for Andhra Pradesh Class 10 Physical Science Textbook Solution or Study Material for AP SSC 10th exam. Here you search will end! Here in this page we have provided for all question answer for Chapter 9 Classification of Elements – The Periodic Table.

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AP 10th Class Physics Chapter 9 Classification of Elements – The Periodic Table Solution

(1) Newlands proposed the law of octaves. Mendeleeff suggested eight groups for elements in histable. How do you explain these observations in terms of modern periodic classification? (AS1)

Ans: –According to Newland the eight element in ascending order to their atomic weight will Show the similar property to the beginning elements. And according to Mendeleeff in a group of elements all will show same property. These two laws describe the property of the elements in a periodic table.


(2) What are the limitations of Mendeleeff’s periodic table? How could the modern periodic table overcome the limitations of Mendeleeff’s table? (AS1)

Ans: –According to Mendeleev’s the physical and chemical properties of any element must be to their atomic mass which seen as a limitations in the law. But in the of the modern periodic table we took atomic no of the element to find its characteristics. To overcome this situation.


(3) Define the modern periodic Law. Discuss the construction of the long form of the periodictable. (AS1)

Ans: –Modern periodic table tells us that the physical and chemical properties of any element will be according to their atomic number or electronic configuration. The long form of the periodic table has 18 vertical line called group and 7 horizontal lines called period.


(4) Explain how the elements are classified into s, p, d and f- block elements in the periodic table and give the advantage of this kind of classification. (AS1)

Ans: –The element are classified into s, p, d, f- block are based on their last electronic configuration. At first the electron enter into s then p and then d and at last f block. By doing this classification we can easily separate the similar property showing element in the same group and different properties of element to the other groups.


(5) Given below is the electronic configuration of elements A, B, C, D. (AS1)

(A) 1s2 2s2 (1)Which are the elements coming within the same period

(B) 1s2 2s2 2p6 3s2. (2) Which are the ones coming within the same group?

(C) 1s2 2s2 2p6 3s23p3 (3) Which are the noble gas elements?

(D) 1s2 2s2 2p6 (4) To which group and period does the elements ‘C’ belong

Ans: –(1) A and the B are coming to the same period.

(2) B and C are coming ones in the same group.

(3) D is the noble gas elements. ; 4.By its electronic configuration we can tell that c belongs to 3rd period and 5th group.


(6) Write down the characteristics of the elements having atomic number 17. (AS1)


  • The electronic configuration of the element is 1s^22s^22p^63s^23p^5.
  • The no of period is 7.
  • The group no is 3.
  • It is p block element.
  • The valance electron or no of electron in last two orbital is 7.
  • It is non-metal


(7) (a) State the number of valence electrons, the group number and the period number of each elementgiven in the following table: (AS1)


Sulphur 6 6 3
Oxygen 6 6 2
Magnesium 2 2 3
Hydrogen 1 1 1
Fluorine 7 7 2
Aluminum 3 3 3


(b) State whether the following elements belong to a Group (G), Period (P) or Neither Group nor Period(N). (AS1)


Element Group No Period no N
Li , C, O 2, 2, 2 1,4, 6  
Mg, Ca, Ba 2, 4, 6 2, 2, 2  
Br, Cl, F 4, 3, 2 7, 7, 7  
C , S, Br 2, 3, 4 4, 6, 7  
Al , Si, Cl 3, 3, 3, 3, 4, 7  
Li , Na , K 2, 3, 4 1, 1, 1  
C, N ,O 2, 2, 2 1, 1, 1  
K , Ca , Br 4, 4, 4 1, 2, 7  


(8) Elements in a group generally possess similar properties, but elements along a period have different properties. How do you explain this statement? (AS1)

Ans:-As the electronic configuration of an element along to the group is same it shows same property. But in a period the valance shell configuration is different so different property shows.


(9) s – block and p – block elements except 18th group elements are sometimes called as ‘Representative elements’ based on their abundant availability in the nature. Is it justified? Why?(AS1)

Ans: –As the s block and p block elements present in nature are abundant they are called the Representative elements but 18th group element are free living so they are not. Most of the compound are made of this two block element.


(10) Complete the following table using the periodic table. (AS1)


Periods No Filling up the orbital


Maximum no of

electron filled in all


Total no of element

present in the


1 1s 2 2
2 2s, 2p 8 8
3 3s, 3p 18 8
4 4s , 3d, 4p 18 18
5 5s, 4d, 5p 18 18
6 6s(4f), 5d, 6p 32 32
7 7s, 5f, 6d, 7p 32 Incomplete


(11) Complete the following table using the periodic table. (AS1)


Element Total no of element
Total no of


Period Number From  TO S block P  block .d block .f block
1 2 H He 1 1 0 0
2 8 Li Ne 2 6 0 0
3 8 Na Ar 2 6 0 0
4 18 K Kr 2 10 6 0
5 18 Rb Xe 2 10 6 0
6 32 Cs Rd 2 9 6 15
7 32 Fr Uuo 2 9 6 15

 (12) The electronic configuration of the elements X, Y and Z are given below?

(a) X = 2 b) Y = 2, 6 c) Z = 2, 8, 2

(i) Which element belongs to second period?

(ii) Which element belongs to second group?

(iii) Which element belongs to 18th group?


(i) Element z belongs to the second period.

(ii)Y belongs to the second group.

(iii) X element belongs to the 18th group.


(13) Identify the element that has the larger atomic radius in each pair of the following and mark it with asymbol (3). (AS1)

(i) Mg or Ca

(ii) Li or Cs

(iii) N or P

(iv) B or Al


(i) Ca has large radius than Mg;

(ii) Cs has more radius.

(iii) Here p has more radius.

(iv) Al has more radius.


(14) Identify the element that has the lower Ionization energy in each pair of the following and mark itwith a symbol (3). (AS1)

(i) Mg or Na

(ii) Li or O

(iii) Br or F

(iv) K or Br


(i) Na has low IE than Mg;

(ii) Li has low ionization energy;

(iii) F has low IE as compare to Br.;

(iv) Khas low IE value.


(15) In period 2, element X is to the right of element Y. Then, find which of the elements have:

(i) Low nuclear charge

(ii) Low atomic size

(iii) High ionization energy

(iv)High electronegativity

(v) More metallic character


(i) y has lower nuclear charge;

(ii) x atomic size is low.

(iii) x has high IE.

(iv) x is high electronegativity.

(V) y is more metallic.


(16) How does metallic character change when we move?

(i) Down a group

(ii) Across a period?


(i) Down a group metallic character increase as the new shell adder and tendency of losing electronrise up.

(ii)Across a period tendency of losing electron decrease as nuclear charge rise so metallic character decrease.


(17) Why was the basis of classification of elements changed from the atomic mass to the atomic number? (AS1)

Ans: –For example tellurium with high atomic weight precede low atomic weight iodine. But if we arrange the element according to their atomic no then there will be no problem.


(18) What is a periodic property? How do the following properties change in a group and period? Explain.(AS1)

(a) Atomic radius

(b) Ionization energy

(c) Electron affinity

(d) Electronegativity.

(b) Explain the ionization energy order in the following sets of elements:

(a) Na, Al, Cl

(b) Li, Be, B

(c) C, N, O

(d) F, Ne, Na

(e) Be, Mg, Ca. (AS1)

Ans: –The arrangements of the elements in the modern periodic table is according to their atomic no.The chemical property of any element depends on their electronic configuration.

(a) Atomic radius of an element decrease left to right in a group as charge increase and for that attraction between the electron increases. Atomic radius down a group increase as charge increase and for that new valance shell get added.

(b) Ionization increase in a period from left to right and down a group it also increase.

(c) Electron affinity increase in a period from left to wright and decrease down a group.

(d) Electronegativity increase from left to wright in a period and decrease down a group.

(b) (a) Na <Al<Cl ;

(b) Li < Be < B;

(c) C< N<O;

(d) Na <F<Ne;

(e) Be> Mg>Ca.


(19) Name two elements that you would expect to have chemical properties similar to Mg.What is the basis for your choice? (AS2)

Ans: – Ca and B has the same property to Mg. As both these element belongs to the same group.


(20) On the basis of atomic numbers predict to which block the elements with atomic number 9, 37, 46 and 64 belongs to? (AS2)

Ans: –From the electronic configuration of these atomic no we can tell the period of these. As atomic no 9 has 7 valance electron so it’s period is 7 and s block element, atomic no 37 has 1valance electron so it’s period is 1 and p block element , atomic no 46 has 10 valance electro so its period is 10 and d block element and at last atomic no 64 is f block element.


(21) Using the periodic table, predict the formula of compound formed between and element X of group 13 and another element Y of group 16. (AS2)

Ans: –Comparing the valency of this element we can predict the formula of the compound will be X2Y5.


(22) An element X belongs to 3rd period and group 2 of the periodic table. State

(a) The no. of valence electrons

(b) The valency

(c) Whether it is metal or a non-metal. (AS2)

Ans: –From the information we can predict that the electron configuration of valance shell of the element be 2s^22p^1.Then

(a) no of valence electron be 1. And(b) valency will be 1;(c) It will be non metal.


(23) An element has atomic number 19. Where would you expect this element in the periodic table and why? (AS2)

Ans: –The electronic configuration of that 19 atomic no element will be1s^22s22p^63s^23p^64s^1. So from its configuration we can say that the valence electron is 1 so period must be 1 and group will be 4.


(25) Collect the information about reactivity of VIII A group elements (noble gases) from internet or from your school library and prepare a report on their special character when compared toother elements of periodic table. (AS4)

Ans: –The noble gas present in the 18th group in the modern periodic table. Its valence shell always filled so it doesn’t react with any element. It called the inert gas. This noble gas being liquid is very rare.


(26) Collect information regarding metallic character of elements of IA group and prepare report to support the idea of metallic character increases in a group as we move from top to bottom.(AS4)

Ans: –The element of 1A group are metallic in character as all have the tendency to lose its valence electron. As we go from up to down in 1A group we will see the electro positivity increases.


(27) How do you appreciate the role of electronic configuration of the atoms of elements inperiodic classification? (AS6)

Ans: –With the help of electronic configuration of any atom we can easily predict the position of that atom. If we know the valency of an atom we can tell about its position in period as well its other characteristics. With the help of its subshell no we can tell its group no.


(28) Without knowing the electronic configurations of the atoms of elements Mendeleev still could arrange the elements nearly close to the arrangements in the Modern periodic table. How can you appreciate this? (AS 6)

Ans: –Mendeleev organize the periodic table according to the increases of atomic mass. The horizontal line in the group is known as period and the vertical is group. He predicted the property of the element now which came to be true it just his brilliance.


(29) Comment on the position of hydrogen in periodic table. (AS7)

Ans: –If we follow the formula of H2 which is same to the other many atom in the periodic table. It has a similar characteristics of alkali metal. Comparing this phenomenon of hydrogen its position on 1 group is debatable.


(30) How the positions of elements in the periodic table help you to predict its chemical properties?Explain with an example. (AS7)

Ans: –The position of the element in the periodic table tell about the ionization energy of the elements, electronegativity, metallic and nonmetallic property etc.

Example: –For example if we take atomic no 9 we can say its group no is 2 and period no is 2, it shows non metallic character.



(1) Lithium, ______sodium_______ and potassium constitute a Determiner’s triad.

(2) __Atomic mass_____ was the basis of the classifications proposed by Dobereiner, Newlands and Mendeleeff.

(3) Noble gases belongs to _____18__________ group of periodic table.

(4) The incomplete period of the periodic table is __7th________

(5) The element at the bottom of a group would be expected to show _more_________ metalliccharacter than the element at the top.



(1) Number of elements present in period – 2 of the long form of periodic table

:- (b) 8.

(2) Nitrogen (Z = 7) is the element of group V of the periodic table. Which of the following is theatomic number of the next element in the group?

:-(c) 15

(3) Electron configuration of an atom is 2, 8, 7 to which of the following elements would it bechemically similar?

(B) Fluorine (9)

(4) Which of the following is the most active metal?


Updated: November 12, 2021 — 2:43 pm

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