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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
Two elements ‘P’ and ‘Q’ belong to the same period of the modern periodic table and are in Group 1 and Group 2, respectively. Compare their following characteristics in tabular form:-
(a) The number of electrons in their atoms
(b) The sizes of their atoms
(c) Their metallic character
(d) Their tendencies to lose electrons
(e) The formula of their oxides
(f) The formula of their chlorides
Calcium is an element with atomic number 20. Stating reason, answer each of the following questions:-
(i) Is calcium a metal or a non-metal?
(ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19?
(iii) Write the formula of its oxide.
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?
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
From the following elements :
4Be; 9F; 19K; 20Ca
(i) Select the element having one electron is the outermost shell.
(ii) two elements of the same group.
Write the formula of and mention the nature of the compound formed by the union of 19K and element X(2, 8, 7).
Consider two elements 'A' (Atomic number 17) and 'B' (Atomic number 19) :
(i) Write the positions of these elements in the modern periodic table giving justification.
(ii) Write the formula of the compound formed when 'A' combines with 'B.'
(iii) Draw the electron dot structure of the compound and state the nature of the bond formed between the two elements.
The following table shows the electronic configuration of the elements W, X, Y, Z:
| Element | w | x | y | z |
| Electronic configurations |
2, 8, 1 | 2, 8, 7 | 2, 5 | 1 |
Answer the following questions based on the table above:
1) What type of Bond is formed between :
a) W and X
b) Y and Z
2) What is the formula of the compound formed between :
a) X and Z
b) W and X
An element Z has atomic number 16. Answer the following questions on Z:
1) State the period and group to which Z belongs
2) Is Z a metal or a non-metal?
3) State the formula between Z and hydrogen
4) What kind of a compound is this?
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Arrange the following elements in the increasing order of their metallic character:
Mg, Ca, K, Ga
Fill in the blank in the following statement:
In going across a period (right to left) in periodic table, the atomic size of the atom ...............
The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm; 104 pm and 143 pm respectively. Giving a reason, arrange these elements in the increasing order of atomic numbers in the period.
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 largest atomic size?
Five elements A, B, C, D and E have atomic numbers of 2, 3, 7, 10 and 18 respectively. The elements which belong to the same period of the periodic table are:
(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E
Which of the following element would lose an electron easily?
(a) Mg
(b) Na
(c) K
(d) Ca
Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?
Which of the following element does not lose an electron easily?
(a) Na
(b) F
(c) Mg
(d) Al
On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?
(a) increases
(b) decreases
(c) remain the same
(d) first increases then decreases
Which of the following set of elements is written correctly in the order of their increasing metallic character?
(a) Mg, Al, Si
(b) C, O, N
(c) Na, Li, K
(d) Be, Mg, Ca
Name two elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?
An element has 2 electrons in its N shell.
State the name assigned to this group.
An element X belong to 4th period and 17th group, state.
no of valence electrons in it
An element X belong to 4th period and 17th group, state.
name the family to which it belong.
Name the element in period 3 which does not form oxide.
name the elements in period 1.
What is the common feature of the electronic configuration of the elements at the end of period 2, and period 3?
An element 'X' (Atomic number – 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
Calculate the valency of element X whose atomic number is 9.
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?
'In a group, the atomic radii increase with increasing period number', explain this statement and justify it with reference to group 17.
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
Arrange the following as per instruction given in the bracket
Na, K, Cl, S, Si (increasing ionisation potential)
Arrange the following in order of increasing radii:
Mg2+, Mg, Mg+
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.
Alkaline earth metal in period 3.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Oxide of first group elements.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Compound formed when an element A of group 2 combines with an element B of group seventeen.
The similarities in the properties of a group of elements are because they have the same ______.
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
