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प्रश्न
Answer the following question:
State the four blocks of the modern periodic table based on the electronic configuration of elements.
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उत्तर
Elements in the modern periodic table are classified on the basis of their electronic configuration. They are divided into four blocks: s – block, p – block, d – block, and f – block.
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संबंधित प्रश्न
The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.
- Calculate the average atomic mass of elements A and C.
- Compare the average atomic mass with atomic mass of B.
- What could the elements A, B and C be?
Name any two elements of group one and write their electronic configurations. What similarity do you observe in their electronic configurations? Write the formula of oxide of any of the aforesaid elements.
The elements 4Be, 12Mg and 20Ca, each having two valence electrons in their valence shells, are in periods 2, 3 and 4 respectively of the modern periodic table. Answer the following questions associated with these elements, giving reason in each case:
(a) In which group should they be?
(b) Which one of them is least reactive?
(c) Which one of them has the largest atomic size?
Write the atomic numbers of two elements 'X' and 'Y' having electronic configuration 2, 8, 2 and 2, 8, 6 respectively.
Write the number of vertical columns in the modern periodic table. What are these columns called?
Match the atomic number 2, 4, 8, 15 and 19 with each of the following:
- A solid non-metal belonging to the third period.
- A metal of valency 1.
- A gaseous element with valency 2.
- An element belonging to Group 2.
- A rare gas.
An element Z has atomic number 16. Answer the following questions on Z:
- State the period and group to which Z belongs.
- Is Z a metal or a non-metal?
- State the formula between Z and hydrogen.
- What kind of a compound is this?
How does the number of valence electrons vary on moving from left or right in the first period of the periodic table?
How does the valency of elements vary in going down a group of the periodic table?
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the periodic table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?
For each of the following triads, name the element with the characteristics specified below:
| Elements | Least atomic radius | Chemically least reactive |
| (i) F, Cl, Br (ii) Li, Na, K |
.................... .................... |
.................... .................... |
In which part of a group would you separately expect the elements to have the greatest metallic character
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
Periodicity is observed due to the similar ______.
How do the following change on moving from left to right in a period of the periodic table?
Give examples in support of your answer.
atomic structure (electron arrangements) ?
An element X belong to 3rd periods and group II of the periodic table state:
the number of valence electrons,
An element X belong to 3rd periods and group II of the periodic table state:
the valency,
An element X belong to 3rd periods and group II of the periodic table state:
name of the element,
Complete the following sentences
The similarities in the properties of a group of elements are because they have the same …………………
On the basis of electronic configuration, how will you identify the first and the last element of a period?
Taking into consideration the period of the elements given below, answer the following questions:
| Elements | Atomic Radius (pm) |
| O | 66 |
| B | 88 |
| C | 77 |
| N | 74 |
| Be | 111 |
| Li | 152 |
- Arrange the above elements in decreasing order of their atomic radii.
- State the period to which the above elements belong.
- Why this arrangement of elements is similar to the above period of modern periodic table?
- Which of the above elements have the biggest and the smallest atom?
- What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?
Arrange the following in increasing order of property indicated
SiO2, P2O5, SO3, Cl2O7 (acidic nature)
An element Z has atomic number 16. Answer the following
(a) State the period and group to which Z belongs
(b) Is Z a metal or a non-metal?
(c) State the formula between Z and hydrogen.
(d) what kind of a compund is this?
Choose the most appropriate answer from the following list of oxides which fit the description.
An oxide which dissolves in water forming an acid.
Choose the most appropriate answer from the following list of oxides which fit the description.
An amphoteric oxide: Al2O3 (shows both acidic and basic properties)
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
To which period do these elements belong?
Name and state the following with reference to the elements of the first three periods of the periodic table.
Alkaline earth metal in period 3.
Going across a period left to right, atomic size _____.
The electronic configuration of an element is 2, 8, 4. State it:
group and period in the Modern Periodic Table.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Oxide of first group elements.
Supply the missing word from those in bracket:
If an element has one electron in its outermost energy level [shell] then it is likely to be _______.
State the property trends in general of elements on moving down in a group of the periodic table.
Name or state following with reference to the element of the first three periods of the periodic table.
A metal in period 3 having valency 3.
Name or state following with reference to the element of the first three periods of the periodic table.
The formula of the hydroxide of the element having electronic configuration 2, 8, 2.
Fill in the blanks from the words A to F given below’.
A: Decreases
B: Increases
C: Remains same
D: Increases by one
E: Electropositive
F: Electronegative
Across a period from left to right in the Modern Periodic Table.
No. of electron shells _________; No. of valence electrons __________: Electronegativity increases Character of elements changes from electropositive to ________.
Electron Affinity is maximum in ______.
