SSLC Chemistry - Chapter 01 Periodic Table and Electronic Configuration - Questions and Answers
Textbooks Solution for Class 10 Chemistry (English Medium) പീരിയോഡിക് ടേബിളും ഇലക്ട്രോണ് വിന്യാസവും | Text Books Solution Chemistry (English Medium) Chapter 01 Periodic Table and Electronic Configuration
Class 10 Chemistry Questions and Answers
Chapter 01 Periodic Table and Electronic Configuration
* According to The Bohr model of an atom, electrons are revolving around the nucleus through fixed circular paths called Orbits or shells. Since each electron is associated with a definite amount of energy, these orbits are also known as Main energy levels. In these main energy levels, different Sub energy levels (Sub shells )are assigned. Sub shells are named as s, p, d, f etc. (s- sharp. p -principal. d- diffuse. f- fundamental)
Orbitals: - orbitals are regions in a subshell where the probability of finding an electron is maximum.
* Distribution of electrons in various subshells
Electrons occupy various subshells according to the increasing order of their energies. This is known as subshell electronic configuration.
It can be understood from the following order.
1s>2s>2p>3s>3p>4s>3d>4p>5s>4d>5p>6s
* Subshell electronic configuration and blocks
The block to which the element belongs will be the same as the subshell to which the last electron is added. In the periodic table, the elements are arranged in s, p, d and f blocks
* s Block Elements
- The elements in which the last electron enters into the s subshell of the outermost shell are called s block elements. These include elements of group I (alkali metals) and group II (Alkaline earth metals)
- In chemical reactions, s block elements donate electrons. Hence they show positive oxidation states.
Alkali metals donate one electron. Hence they show +1 oxidation state.
Alkaline earth metals donate two-electron. Hence they show +2 oxidation state.
- For s block elements the number of electrons in the outermost s subshell will be the group number.
* The characteristics of s block elements (Summary)
- Metallic nature.
- Low ionization energy.
(Only a small amount of energy is needed to remove a weakly bonded electron)
- Low electronegativity. (Tendency to attract electron is less as they donate electrons)
- Lose electrons in chemical reactions.
- Compounds are mostly ionic.
- Elements of group 1 have greater reactivity in their respective periods.
- Oxides and Hydroxides are basic in nature.
- Highest atomic radius in the respective periods.
- Reactivity increases down the group.
* 'p' block elements
- The elements in which the last electron goes to the p subshell of the outermost shell are called p block elements.
- The p block consists of elements of group 13 to 18.
- Elements of solid, liquid and gaseous states at room temperature are present in p block.
- Most of the elements of group 18 are chemically inert.
- Among the p block elements, the highest reactivity is shown by group 17 elements.
- They show higher ionisation energy and electronegativity than s block elements.
- Metallic Character increases down the group (Decreases along a period).
- The group number of p block elements can be obtained by adding 10 to the total number of electrons in the s and p subshell of the outermost shell. (s+ p+10)
* 'd' block elements
- The elements in which the last electron goes to the d subshell of the Penultimate shell are called d block elements.
- The d block consists of elements of group 3 to 12 of the periodic table.
- They are also known as Transition elements. (The word transition refers to a slow but steady change from one to the other)
- These are all metals
- They show similarity in properties not only in a group but also in a period
- The show variable oxidation states.
- Most of their ions and compounds are coloured.
- Many transition metals or their compounds are good catalysts.
- The group number of the d block elements will be the same as the sum of electrons in the outermost s subshell and the number of electrons in the preceding d subshell. (s+d)
* The 'f ' block elements
- The elements in which the last electron enters into the f subshell of the antepenultimate shell are called f block elements.
- The f block elements are the elements coming after lanthanum and actinium and are placed in two rows at the bottom of the periodic table.
- They are arranged in the 6th and 7th period of the periodic table in two separate raws. The first raw is called Lanthaniods. The second raw is called Actinides
- Like d block elements, they also show variable oxidation states.
- Most of the actinoids are radioactive and are artificial elements.
- Uranium (U), Thorium (Th), Plutonium etc are used fuels in nuclear reactors.
- Many of them are used as catalysts in the petroleum industry.
* QUESTIONS WITH ANSWER
1. What is the basis of the classification of elements in the modern periodic table?
Answer: Atomic Number.
1. There are three shells in the sodium atom. Which is the shell that possesses the greatest energy?
Answer: M shell.
2. What is the relation between the energy of a shell and its distance from the nucleus?
Answer: Energy increases with the increase in distance.
4. Which is the energy level having only one subshell?
Answer: K shell.
5. How many subshells are there in shell L? Which are they?
Answer: 2. s & P
6. Which subshell is common to all shells?
Answer: 's' subshell
7. Write down the subshell electronic configuration of the atoms ₁₁Na& ₁₇ Cl and find the period they belong.
Answer: Na – 1s² 2s² 2p⁶ 3s¹ Period. 3
Cl-1s² 2s² 2p⁶ 3s² 3p⁵ Period. 3
Note: Highest shell number is the period.
8. If the outermost subshell electronic configuration of an atom is 3p³ find its atomic number, block and group.
Answer: Complete electronic configuration is: 1s² 2s² 2p⁶ 3s² 3p³
Atomic number – 15 (total number of electrons),
Block - p (the subshell in which the last electron is filled)
Group - 3+12=15,
9. Arrange the subshells 1s, 2s, 2p, 3s, 3p,3s,3p,3d,4s, 4p in the ascending order of their energy.
Answer: 1s> 2s>2p> 3s> 3p>3s>3p>4s> 3d>4p
10. The Atomic number of an element is 23. Find its block, group, period from its electronic configuration.
Answer: 1s² 2s² 2p⁶ 3s² 3p³ 3d³ 4s²
Block: d Group: 3+2 =5 Period: 4
11. Atomic number of calcium is 20. Write down the electronic configuration of the calcium atom and find its block, group and period.
Answer: ₂₀Ca: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
Block: s Group: 2 Period:4
12. Give three important features of 'd' block elements.
Answer:
* Shows variable oxidation states.
* Most of the compounds are coloured.
* Show similarities in chemical properties in the period as well as in groups.
13. Some features of elements are given below. Classify them as s,p,d & f elements.
a. Shows variable oxidation state.
b. Alkali metal.
c. Used as a catalyst in the Petroleum industry.
d. Definite positive oxidation state.
e. Last electron is filled in a penultimate shell.
f. Alkaline earth metal.
g. Consists elements of positive and negative oxidation state.
h. Radioactive elements.
i. Last electron is filled anti penultimate shell.
Answer:
s block: b,d,f p block:g d block:a,e f block: a,c,h,i
14. Write down oxidation states of iron in the compounds of FeCl₂& FeCl₃ (Oxidation state of Cl is -1)
Answer: FeCl₂: 2, FeCl₃ : 3
15. Give the electronic configuration Manganese ion in the compound of MnO₂.
Hint: Oxidation state of oxygen: -2, Atomic number of Manganese: 25
Answer: Oxidation number of Manganese ion is +4.
Electronic configuration of Manganese atom: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²
Electronic configuration of Mn⁴⁺: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³
16. Give two examples for f block elements.
Answer: Uranium and Thorium
17. Find the relation of the first pair and complete the second pair accordingly.
a. Period-7: Actinoids; ...........: Lanthanoids
b. Lanthanoids: 4f¹; Actinoids: ......
c. Sub shells: Sub energy levels; Shells: .......
Answer:
a. Period.6
b. 5f¹
c. Principal energy levels
18. Of the compounds copper sulphate(CuSO₄), Potassium chloride (KCl), Potassium permanganate (KMNO₄) which are likely to be coloured compounds. Justify your answer.
Answer: As copper sulphate(CuSO₄) and Potassium permanganate (KMNO₄) are the compounds of 'd' block elements, they are likely to be coloured.
19. Lanthanoids and actinoids are 'f' block elements. What are the two major differences between them?
Answer:
20. In an atom the last two electrons are filled in the subshell 3d.
Write down the complete electronic configuration. Also find its atomic number, period, block, group of the element.
Answer: Electronic configuration. 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s²
Atomic number - 22 Period - 4 Block - d Group - 2+2 = 4
21. Copper is an element that shows +1 & +2 oxidation state. The atomic number of copper is 29.
a. Give electronic configuration of copper, Cu⁺¹, Cu⁺²
b. Write down the chemical formula of two compounds formed when the copper reacts with chlorine (₁₇Cl).
Answer:
a. (i) Cu: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹
(ii) Cu⁺¹: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰
(iii) Cu⁺²: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹
b. CuCl, CuCl₂
22. A part of the periodic table is given. The symbols of elements are not real.
b. Which are the elements that show variable oxidation states?
c. Find out the larger alkali metal
e. In element B, which is the subshell in which the last electron is filled?
Answer:
a. E, F & G
b. C&D
c. B
d. G
e. S subshell
23. Write down the oxidation number of the d block elements in the following compounds.
i. FeCl₃
ii. MnCl₂
iii. CuO
iv. MnO₂
v. Mn₂O₃
vi. Mn₂O₇
Answer:
i. FeCl₃: Fe³⁺ - Oxidation number: +3
ii. MnCl₂: Mn²⁺ - Oxidation number: +2
iii. CuO: Cu2²⁺ - Oxidation number: +2
iv. MnO₂: Mn⁴⁺ - Oxidation number: +4
v. Mn₂O₃: Mn³⁺ - Oxidation number: +3
vi. Mn₂O₇: Mn⁷⁺ - Oxidation number: +7
24. Give one common property of d block elements and f block elements.
Answer: Both d block elements and f block elements show variable oxidation states.
25. Electronic configuration of chromium (₂₄Cr) is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
a. Is there any change in the filling of electrons in this atom? If yes what is the reason for this change?
b. Give one more example for such an element.
Answer:
a. Yes. There is a slight change in electron filling.
The half-filled or full-filled d subshell is more stable than others. In chromium, this change in the filling made the d subshell half-filled and hence more stable.
b. Copper.
26. Iron with atomic number 26 shows +3 oxidation state in a chemical reaction.
a. Write the subshell electronic configuration of Fe.
b. Write the subshell electronic configuration of the ion formed.
c. Write whether the element can show a different oxidation state. Justify?
Answer:
a. 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s²
b. 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵
c. Yes. The d block elements can lose electrons from the outermost s subshell and inner d subshell
Let’s Assess (TextBook Questions: Page 29, 30)
27. Based on the hints given, find out the atomic number and write down the subshell electronic configuration of elements (Symbols used are not real).
i) A- period 3 group 17
ii) B- period 4 group 6
Answer:
i) A- 1s² 2s² 2p⁶ 3s² 3p⁵
ii) B- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
28. When the last electron of an atom was filled in the 3d subshell, the subshell electronic configuration was 3d⁸. Answer the questions related to this atom.
* Complete subshell electronic configuration
* Atomic number
* Block
* Period number
* Group number
Answer:
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s²
● Atomic Number= 28
● Block= d
● Period = 4
● Group= 10
29. Pick out the wrong subshell electronic configurations from those given below.
a) 1s² 2s² 2p⁷
b) 1s² 2s² 2p²
c) 1s² 2s² 2p⁵ 3s¹
d) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s¹
e) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s²
Answer: a,c,d
30. The element X in group 17 has 3 shells. If so,
a) Write the subshell electronic configuration of the element.
b) Write the period number.
c) What will be the chemical formula of the compound formed if the element X reacts with Y of the third period which contains one electron in the p subshell?
Answer:
a) 1s² 2s² 2p⁶ 3s² 3p⁵
b) 3
c) YX₃
31. The element Cu with atomic number 29 undergoes a chemical reaction to form an ion with oxidation number +2.
a) Write down the subshell electronic configuration of this ion?
b) Can this element show variable valency? Why?
c) Write down the chemical formula of one compound formed when this element reacts with chlorine (₁₇Cl).
Answer:
a) Cu²⁺ , 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹
b) Yes it can. It is a d block element. In d block elements, there is only a slight difference in the energy between the Outermost s subshell and the penultimate d subshell. On some occasions, these inner d electrons may participate in chemical reactions in addition to the outermost s
electrons. Hence they show variable oxidation valency (Oxidation state)
c) CuCl and CuCl₂
32. Certain subshells are given below.
2s, 2d, 3f, 3d, 5s, 3p
a) Which are the subshells that are not possible?
b) Give reason.
Answer:
a) 2d, 3f
b) Only two subshells are possible for the second shell. They are s and p
Only two subshells are possible for the third shell. They are s, p and d
CHEMISTRY Textbook (pdf) - Click here
PSC Solved Question Papers ---> Click here
PSC TODAY's EXAM RESULTS ---> Click here
PSC EXAM PROGRAMME -> Click here
CURRENT AFFAIRS QUESTIONS -> Click here
PSC Degree Level Questions & Answers - Click here
PSC 10th, +2 Level Questions & Answers - Click here
PSC SHORTLISTS -> Click here
PSC RANK LISTS -> Click here
 Chapter 01 PERIODIC TABLE AND ELECTRONIC CONFIGURATION){kind=link}
0 Comments