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प्रश्न
Rearrange the columns 2 and 3 so as to match with the column 1.
| Column 1 | Column 2 | Column 3 |
| i. Triad ii. Octave iii. Atomic number iv. Period v. Nucleus vi. Electron |
a. Lightest and negatively charged particle in all the atoms b. Concentrated mass and positive charge c. Average of the first and the third atomic mass d. Properties of the eighth element similar to the first e. Positive charge on the nucleus f. Sequential change in molecular formulae |
1.Mendeleev
2. Thomson
3. Newlands
4. Rutherford
5. Dobereiner
. Moseley
|
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उत्तर
|
Column I
|
Column II
|
Column III
|
| i. Triad | c. Average of the first and the third atomic mass | 5. Dobereiner |
| ii. Octave | d. Properties of the eight-element similar to the first. | 3. Newlands |
| iii. Atomic Number | e. Positive charge on the nucleus. | 6. Moseley |
| iv. Period | f. Sequential change in molecular formulae | 1. Mendeleev |
| v. Nucleus | b. Concentrated mass and positive charge | 4. Rutherford |
| vi. Electron | a. Lightest and negatively charged particle in all the atoms | 2. Thomson |
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संबंधित प्रश्न
State whether the following statement is true of false:
The elements in a group have consecutive atomic numbers.
The element which forms a basis oxide has the atomic number of:
(a) 18
(b) 17
(c) 14
(d) 19
The elements A, B and C belong to groups 1, 14, and 17 respectively of the periodic table.
(a) Which two elements will form a covalent compound?
(b) Which two elements will form an ionic compound?
Find the neutral atom in the periodic table which has the same number of electrons as K+ and Cl−. What is this number?
A non-metal X which is the largest constituent of air combines with hydrogen when heated in the presence of iron as catalyst to form a gas Y. When gas Y is treated with sulphuric acid, it forms a compound Z which is used as a chemical fertiliser.
(a) What are X, Y and Z?
(b) To which group of periodic table does X belong?
(c) Name the periodic table in which X is placed.
(d) Which element is placed just before X in the period?
(e) Which element is placed just after X in the period?
The elements Li, Na and K, each having one valence electron, are in period 2, 3 and 4 respectively of modern periodic table.
(i) In which group of the periodic table should they be ?
(ii) Which one of them is least reactive ?
(iii) Which one of them has the largest atomic radius ? Give reason in justify your answer in each case.
Two elements X and Y belong to group 1 and 2 respectively in the same period of periodic table. Compare them with respect to:
(i) the number of valence electrons in their atoms
(ii) their valencies
(iii) metallic character
(iv) the sizes of their atoms
(v) the formulae of their oxides
(vi) the formulae of their chlorides
What was the basis of the earliest attempts made for classification and grouping of elements?
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was ______.
Example for liquid metal is ______.
If the distance between two Cl atoms in a Cl2 molecule is 1.98Å, then the radius of the Cl atom is ______.
Identify the bond between H and F in the HF molecules.
The elements of group 16 are called ______
Which of the following elements does not lose an electron easily?
The element with atomic number 26 will be found in group ______
Identify and name the metals out of the following elements whose electronic configurations are given below.
- 2, 8, 2
- 2, 8, 1
- 2, 8, 7
- 2, 1
Complete the following cross word puzzle
Across:
(1) An element with atomic number 12.
(3) Metal used in making cans and member of Group 14.
(4) A lustrous non-metal which has 7 electrons in its outermost shell.
Down:
(2) Highly reactive and soft metal which imparts yellow colour when subjected to flame and is kept in kerosene.
(5) The first element of second Period
(6) An element which is used in making fluorescent bulbs and is second member of Group 18 in the Modern Periodic Table
(7) A radioactive element which is the last member of halogen family.
(8) Metal which is an important constituent of steel and forms rust when exposed to moist air.
(9) The first metalloid in Modern Periodic Table whose fibres are used in making bullet-proof vests
Complete the following table:
| Symbol | Atomic No | Electronic Configuration | |
| 1. | He | 2 | ______ |
| 2. | Ne | ______ | 2,8 |
| 3. | Ar | ______ | 2, 8,8 |
| 4. | Na | 11 | ______ |
Identify the following:
An element in Period 1 which can be placed in both Group 1 and Group 17 of the Periodic Table.
