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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 | a. Lightest and negatively charged particle in all the atoms | 1. Mendeleev |
| ii. Octave | b. Concentrated mass and positive charge | 2. Thomson |
| iii. Atomic number | c. Average of the first and the third atomic mass | 3. Newlands |
| iv. Period | d. Properties of the eighth element similar to the first | 4. Rutherford |
| v. Nucleus | e. Positive charge on the nucleus | 5. Dobereiner |
| vi. Electron | f. Sequential change in molecular formulae | 6. 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.
Rewrite the following statement after correction, if necessary:
Periods are the horizontal rows of elements.
An element X is in group 2 of the periodic table What will be the formula of its chloride?
Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electron shells but different number of electrons in their outermost shells. It was found that elements A and G combine to form an ionic compound. This ionic compound is added in a small amount to almost all vegetables and dishes during cooking. Oxides of elements A and B are basis in nature while those of elements E and F acidic. The oxide of element D is, however, almost neutral. Based on the above information, answer the following questions:
(a) To which group or period of the periodic table do these elements belong?
(b) What would be the nature of compound formed by a combination of elements B and F?
(c) Which two of these elements could definitely be metals?
(d) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(e) If the number of electrons in the outermost shell of elements C and G be 3 and 7 respectively, write formula of the compound formed by the combination of C and G.
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?
An element X (atomic number 17) reacts with an element Y (atomic number 20) to form a compound.
(a) Write the position of these elements in the modern periodic table.
(b) Write the formula of the compound formed.
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
Alkaline earth metals have valency 2. This means that their position in the modern periodic table is in ______.
The molecular formula of the chloride of element X is XCl. This compound is a solid having a high melting point. Which of the following elements be present in the same group as X.
In which block of the modern periodic table are the nonmetals found?
How did the early chemists classify elements?
Why was this basis of classification discarded for future classification of elements?
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 |
Which one of the following statements is not correct about the trends in the properties of the elements of a period on going from left to right?
The atom of an element has electronic configuration 2, 8, 7. To which of the following elements would it be chemically similar?
Element ‘A’ has electronic configuration 2, 7; ‘B’ has electronic configuration 2, 8, 5 and ‘C’ has electronic configuration 2, 8, 7. Which two elements will exhibit similar chemical properties?
Which of the following elements does not lose an electron easily?
An element is placed in 2nd Group and 3rd Period of the Periodic Table, burns in presence of oxygen to form a basic oxide.
- Identify the element
- Write the electronic configuration
- Write the balanced equation when it burns in the presence of air
- Write a balanced equation when this oxide is dissolved in water
- Draw the electron dot structure for the formation of this oxide
Relate the names of the following scientists with the statements given below.
Arranged elements in a group of seven with increasing atomic masses and eighth elements with similar properties kept below the first like eight note in an act of music.
