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प्रश्न
Differentiate between Normal elements and Transition elements.
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उत्तर
| Normal Elements | Transition Elements |
| Elements belonging to groups 1 and 2, and 13 to 17 are called normal elements. | Elements belonging to groups 3 to 12 are called transition elements. |
| In these elements, all the inner shells are completely filled except the outermost shells. |
In these elements, the outermost shell and next to the outermost shell (penultimate shell) are incomplete. |
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संबंधित प्रश्न
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 'M' with electronic configuration (2, 8, 2) combines separately with (NO3)–, (SO4)2– and (PO4)3– radicals. Write the formula of the three compounds so formed. To which group and period of the Modern Periodic Table does the element 'M' belong? Will 'M' form covalent or ionic compounds? Give reason to justify your answer.
List any two properties of the elements belonging to the first group of the modern periodic table.
Write the number of horizontal rows in the modern periodic table. What are these rows called?
Name the element that has two shells, both of which are completely filled with electrons.
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.
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
The metal of Group 2 from top to bottom arc Be, Mg, Ca, Sr, and Ba.
1) Which one of these elements will form ions most readily and why?
2) State the common feature in the electronic configuration of all these elements.
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?
State one reason for keeping fluorine and chlorine in the same of the periodic table.
In which part of a group would you separately expect the elements to have the largest atomic size?
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
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
The atomic numbers of the elements Na, Mg, K and Ca are 11, 12, 19 and 20 respectively. The element having the largest atomic radius is:
(a) Mg
(b) Na
(c) K
(d) Ca
In each of the following pair, choose the atom having the bigger size:
(a) Mg (At. No.12) or Cl (At. No.17)
The atomic numbers of three elements A, B and C are given below:
| Element | Atomic number |
| A | 5 |
| B | 7 |
| C | 10 |
(i) Which element belongs to group 18?
(ii) Which element belongs to group 15?
(iii) Which element belongs to group 13?
(iv) To which period/periods do these elements belong?
What do you understand by periodicity?
Why are noble gases placed in a separate group?
Name two elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?
State the valency of the elements of periods 3 and write the formula of their oxides.
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.
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 the reason for each.
Calculate the valency of element X whose atomic number is 9.
What is meant by periodicity of elements?
Explain, the statement 'In each period, the atomic radii gradually decrease with increase in atomic number'. Give one example to justify your answer.
What is the common feature of electronic configurations of the elements at the end of period 2 and period 3?
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
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)
Arrange the following as per instruction given in the bracket.
Mg, Cl, Na, S, Si (decreasing order of atomic size)
Arrange the following as per instruction given in the bracket.
Cs, Na, Li, K, Rb (increasing metallic character)
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?
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 |
State which is most reactive (i) metal (ii) non-metal
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.
An element A has 2 electrons in its fourth shell. State:
its valency
(a) Fill in the blanks and rewrite the completed statements:
(i) ________ group in the periodic table contains elements that are all gases at room temperature.
(ii) Very fine particles mainly scatter ______ light.
