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प्रश्न
Right or wrong sentence.
The modern periodic table shows the molecular masses of the elements in each frame.
विकल्प
Right
Wrong
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उत्तर
The given sentence is wrong.
Explanation:
The modern periodic table shows each element’s atomic number (and often its atomic/relative atomic mass) in the cell; it does not show a “molecular mass”. Elements have atomic masses; “molecular mass” refers to compounds (molecules).
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संबंधित प्रश्न
The position of three elements A, B and C in the Periodic Table are shown below –
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Group 16
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Group 17
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A
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B
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C
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(a) State whether A is a metal or non-metal.
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?
(d) Which type of ion, cation or anion, will be formed by element A?
In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21, and 38. Which of these have physical and chemical properties resembling calcium?
Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic character of elements vary on moving down a vertical column? How does the size of atomic radius vary on moving left to right in a horizontal row? Give reason in support of your answer in the above two cases.
Why do all the elements of the same group have similar properties?
State modern periodic law.
How were the positions of cobalt and nickel resolved in the modern periodic table?
where should hydrogen be placed in the modern periodic table? Give reason for your answer.
On which side of the periodic table will you find metals?
What is the name of those elements which divide metals and non-metals in the periodic table?
Which of the following statement is correct in regard to the classification of elements?
(a) Elements in modern periodic table are arranged on the basis of increasing atomic masses.
(b) Elements in Mendeleev's periodic table are arranged on the basis of increasing atomic numbers.
(c) In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass.
(d) In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.
How would the tendency to lose electrons change as we go from left to right across a period of the periodic table?
How does the chemical reactivity of alkali metals vary on going in group 1 of the periodic table?
Explain why All the elements of a group have similar chemical properties.
In what respects do the properties of group 1 elements differ from those of group 17 elements? Explain with examples by taking one element from each group.
Consider the following elements:
20Ca, 8O, 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be:
(i) very stable?
(ii) in group 2 of the periodic table?
(iii) in group 16 of the periodic table?
Answer the following in respect of element `31/15 P `
To which group and period does it belong?
Write the number of protons, neutrons and electronic configuration of \[\ce{_19^39K, _15^31P}\]. Also state their position in periodic table.
Answer the following in respect of element `31/15 P`
Give its electronic configuration
An element barium has the atomic number 56. Look up its position in the periodic table and answer the following question.
Is it larger or smaller than caesium (Cs)?
Name the noble gas with 3 shells.
An element E has following electronic configuration:
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K |
L |
M |
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2 |
8 |
6 |
(a) To which group of the periodic table does element E belong?
(b) To which period of the periodic table does element E belong?
(c) State the number of valence electrons present in element E.
(d) State the valency of the element E.
Define the atomic size.
Give the symbol and valency of the following element and radical.
Sulphate
State what the group number in the Modern Periodic Table signifies. Give a reason why elements in the same group, have similar valency and similar chemical properties.
Answer the following question in one sentence.
The modern periodic table is divided into which blocks?
Right or wrong sentence.
The modern periodic table has 1 to 7 periods.
An X element with atomic number 11 and Y element with atomic number 13 belongs to the third period in the modern periodic table. With this information, give the answers of the below questions.
- Which element has more metallic character from these two elements?
- What is the valency of each X and Y elements?
- Atom size of Y element is smaller than atom size of X element. Explain.
Element ‘X’ forms a chloride with the formula XCl2, which is solid with a high melting point. X would most likely be in the same group of the periodic table as: ______
Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?
Which one of the following elements exhibit maximum number of valence electrons?
The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. What is such an arrangement of elements called as? Give one example of such a set of elements.
The maximum number of electrons that can be accommodated in s, p,d, and f subshells are ______.
Spot the error:
The elements of group 13 are called the carbon family.
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Write the molecular formula of the compound formed by the combination:
E and B
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Which of the element is a Noble gas?
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Which of the element is a Metalloid?
Give the criteria on the basis of which elements are placed (i) in a group and (ii) in a period in the modern periodic table. The atomic number of an element is 16. According to the criteria, in which group and period it should be placed?
Name the metalloids in the first twenty elements.
