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प्रश्न
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was ______.
उत्तर
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was atomic masses
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संबंधित प्रश्न
An atom has the electron structure of 2, 7.
(a) What is the atomic number of this atom?
(b) To which of the following would it be chemically similar?
7N, 15P, 17Cl, 18Ar
(c) Why would you expect it to be similar?
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
|
Give a reason why elements need to be properly classified.
Match the following
| 1. | Galvanisation | Noble gas elements |
| 2. | Calcination | Coating with Zn |
| 3. | Redox reaction | Silver-tin amalgam |
| 4. | Dental filling | Alumino thermic process |
| 5. | Group 18 elements | Heating in the absence of air |
Moseley’s periodic table is based on atomic mass.
The elements A, B, and C belong to groups 1, 14, and 17 respectively of the Periodic Table. Which two elements will form ionic compounds?
Name the neutral atom in the Periodic Table which has the same number of electrons as K+ and Cl-.
The element with atomic number 26 will be found in group ______
Complete the following triads by inserting the missing elements.
Cl, ______, I
Complete the following table:
| Symbol | Atomic No | Electronic Configuration | |
| 1. | He | 2 | ______ |
| 2. | Ne | ______ | 2,8 |
| 3. | Ar | ______ | 2, 8,8 |
| 4. | Na | 11 | ______ |
