The Periodic Table Exe-5C Structured Answer Chemistry Class-9 ICSE Selina Publishers Solutions Chapter-5. Step By Step ICSE Selina Concise Solutions of Chapter-5 The Periodic Table with All Exercise including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type, Numerical and Structured/Application Questions Solved . Visit official Website CISCE for detail information about ICSE Board Class-9.
The Periodic Table Exe-5C Structured Answer Chemistry Class-9 ICSE Concise Selina Publishers
| Board | ICSE |
| Publications | Selina Publication |
| Subject | Chemistry |
| Class | 9th |
| Chapter-5 | The Periodic Table |
| Book Name | Concise |
| Topics | Solution of Exercise – 5C Structured/Application/Skill Answer type |
| Academic Session | 2023-2024 |
Exercise – 5C Structured/Application/Skill Answer type
The Periodic Table Class-9 Chemistry Concise Solutions
Page-101
Question 1.
| Western music Do | Re | Me | Fa | So | La | Ti |
|---|---|---|---|---|---|---|
| Indian music Sa | Re | Ga | Ma | Pa | Dha | Nee |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| H | Li | Be | B | C | N | O |
| F | Na | Mg | Al | Si | P | S |
| Cl | K | Ca | Cr | Ti | Mn | Fe |
(a) Name the scientist who gave this table.
(b) Which group of elements were not known at his time?
(c) This system worked quite well for the ………….. (heavier/lighter) elements.
(d) The table shown above relates the properties of the elements to their ………….. (atomic number / atomic mass)
(e) Why was this table discarded?
Answer:
(a) John Newland
(b) 18th group of inert elements
(c) This system worked quite well for the lighter elements.
(d) The table shown above relates the properties of the elements to their atomic mass.
(e) Reasons for discarding the law of octaves:
- This classification did not work for heavier elements i.e., those lying beyond calcium. As more and more of elements were discovered, they could not be fitted in this table.
- Newland adjusted two elements cobalt (Co) and nickel (Ni) in the same slot and these were placed in the same column as fluorine, chlorine and bromine which have very different properties than these elements.
- Iron, which resembles cobalt and nickle in properties, has been placed far away from these elements.
Question 2.
(a) Complete the table.
| Atomic No | Element | Electronic configuration | Select element of the same group |
|---|---|---|---|
| 11 | Sodium | …………… | (Ca/N/K) |
| 15 | Phosphorus | …………… | (Al/N/C) |
| 16 | Sulphur | …………… | (F/Cl/O) |
| 9 | Fluorine | …………… | (Ca/Cl/K) |
(b) Classify the elements given in the table as metals and non-metals.
(c) To which group does sodium belong? Why is Hydrogen not considered while describing the elements of this group?
Answer:
(a) The completed table is given below:
| Atomic No | Element | Electronic configuration | Select element of the same group |
|---|---|---|---|
| 11 | Sodium | 2, 8, 1 | K |
| 15 | Phosphorus | 2, 8, 5 | N |
| 16 | Sulphur | 2, 8, 6 | O |
| 9 | Fluorine | 2, 7 | Cl |
(b)
| Element | Metal/Non-metal |
|---|---|
| Sodium (Na) | Metal |
| Phosphorous (P) | Non-metal |
| Sulphur (S) | Non-metal |
| Fluorine (F) | Non-metal |
(c) Sodium belongs to group 1.
Position of hydrogen is not satisfactory. Hydrogen atom is very small in size and therefore many of its properties are different from group 1 elements (alkali metals). It is a gas at room temperature, while other elements of group 1 are solid metals. Secondly, it does not readily form cations, in most compounds, whereas group 1 metals readily form cations and form only ionic bonds. Due to these reasons Hydrogen is not considered while describing the elements of group 1.
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