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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
Write the electronic configuration of K and Ne.
Given below are some elements of the modern periodic table. Atomic number of the element is given in parentheses.
A(4), B(9), C(14), D(19), E(20)
(a) Select the element that has one electron in the outermost shell. Also, write the electronic configuration of this element.
(b) Which two elements amongst these belong to the same group? Give reasons for your answer.
(c) Which two elements amongst these belong to the same period? Which one of the two has bigger atomic radius?
An element 'X' has mass number 35 and number of neutrons 18. Write atomic number and electronic configuration of 'X'. Also write group number, period number and valency of 'X'.
Two elements ‘A’ and ‘B’ belong to the 3rd period of Modern periodic table and are in group 2 and 13, respectively. Compare their following characteristics in tabular form:-
(a) Number of electrons in their atoms
(b) Size of their atoms
(c) Their tendencies to lose electrons
(d) The formula of their oxides
(e) Their metallic character
(f) The formula of their chlorides
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
How do the valency and the atomic size of the elements vary while going from left to right along a period in the modern periodic table?
Write any one difference in the electronic configurations of group-1 and group-2 elements ?
Which element has the electronic configuration 2, 8, 2?
Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)
An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is ______.
Calculate the mass of Calcium that will contain the same number of the atom as are present in 3.2 gm of Sulphur.
[Atomic masses: S=32, Ca=40]
Name the element which is in first group and third period.
How does the size of atoms (atomic size) generally vary in going from left to right in a period of the periodic table? Why does it vary this way?
The electronic configuration of the atom of an element X is 2, 8, 4. In modern periodic table, the element X is places in :
(a) 2nd group
(b) 4th group
(c) 14th group
(d) 8th group
The atomic number of an element is 20. In modern periodic table, this element is placed:
(a) 2nd period
(b) 4th period
(c) 3rd period
(d) 1st period
Which one of the following does not increase while moving down the group of the periodic table?
Periodicity is observed due to the similar ______.
An element has 2 electrons in its N shell.
State the name assigned to this group.
Complete the following sentences.
The properties of the elements are a periodic function of their …………… (atomic number, mass number, reative atomic mass).
F, Cl and Br are the elements each having seven valence electrons. Which of these (i) has the largest atomic radius, (ii) is most reactive? Justify your answer stating reason for each.
How do you calculate the possible valency of an element from the electronic configuration of its atoms?
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?
What is modern periodic law?
How could the atomic radius of a noble gas be compared with the other elements in a period?
'In a group, the atomic radii increase with increasing period number', explain this statement and justify it with reference to group 17.
What is meant by a group in the periodic table?
Parts (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non metallic character of the elements:
(a) Decreases
(b) Increases
(c) Remains the same
(d) Depends on the period
(ii) The electro negativity
(a) Depends on the number of valence electrons
(b) Remains the same
(c) Decreases
(d) Increases
(iii) The ionization potential
(a) Goes up and down
(b) Decreases
(c) Increases
(d) Remains the same
(iv) The atomic size
(a) Decreases
(b) Increases
(c) Remains the same
(d) Sometimes increases and sometimes decreases
(v) The electron affinity of the elements in groups 1 to 7:
(a) Goes up and down
(b) Decreases and then increases
(c) Increases
(d) decreases
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
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 |
One element of this period is missing. Which is the missing element and where should it be placed?
With reference to the variation of properties in the Periodic table, which of the following is generally true?
The position of elements A, B, C, D and E in the periodic table are shown below:
|
Group 1 |
Group 2 |
Group 17 |
Group 18 |
|
|
|
|
D |
|
|
B |
C |
|
|
A |
|
|
E |
Which type of ion will be formed by elements A, B, and C.
Name and state the following with reference to the elements of the first three periods of the periodic table.
Non-metallic elements present in Period 3 of Groups 15 and 16.
An element A has 2 electrons in its fourth shell. State:
is it a metal or non-metal
The electronic configuration of an element is 2, 8, 4. State it:
group and period in the Modern Periodic Table.
Write the electronic configuration of two elements A and B whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element A reacts with element B. State whether this compound is acidic, basic or neutral. Give a reason to justify your answer.
Name the elements in Period 1.
Select the correct answer from the options given below.
It is a metal in period 2 having electronic configuration 2, 1?
State the following:
The group which contains highly electropositive metals including sodium.
