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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 position of eight elements in the Modern Periodic Table is given below where atomic numbers of elements are given in the parenthesis.
| Period No. | ||
| 2 | Li(3) | Be(4) |
| 3 | Na(11) | Mg(12) |
| 4 | K(19) | Ca(20) |
| 5 | Rb(37) | Sr(38) |
(i) Write the electronic configuration of Ca.
(ii) Predict the number of valence electrons in Rb.
(iii) What is the number of shells in Sr?
(iv) Predict whether K is a metal or a non – metal.
(v) Which one of these elements has the largest atom in size?
(vi) Arrange Be, Ca, Mg and Rb in the increasing order of the size of their respective atoms.
Based on the group valency of elements state the formula lot the following giving justification for each :-
(i) Oxides of 1st group elements,
(ii) Halides of the elements of group 13, and
(iii) Compounds formed when an element of group 2 combines with, an element of group 16.
Consider two elements 'X' (Atomic number 17) and 'Y' (Atomic number 20)
(i) Write the positions of these elements in the modern periodic table giving justification.
(ii) Write the formula of the compound formed by the combination of 'X' and 'Y'.
(iii) Draw the electron-dot structure of the compound formed and state the nature of the bond formed between the two elements ?
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?
In the following set of element, one element does not belong to the set. Select this element and state why it does not belong:
Calcium, Magnesium, Sodium, Beryllium
What happens to the metallic character of the elements as we go down in a group of the periodic table?
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
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.
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?
How does the atomic size vary on going down from top to bottom in a group of the periodic table? Why does it vary this way?
In which part of a group would you separately expect the elements to have the greatest metallic character
Which of the following element does not lose an electron easily?
(a) Na
(b) F
(c) Mg
(d) Al
The correct increasing order of the atomic radii of the elements oxygen, fluorine and nitrogen is:
(a) O, F, N
(b) N, F, O
(c) O, N, F
(d) F, O, N
What do you understand by periodicity?
Why are noble gases placed in a separate group?
State the trends in physical properties on moving down the group. Give an example to illustrate.
An element X belong to 4th period and 17th group, state.
no of valence electrons in it
Complete the following sentences
The similarities in the properties of a group of elements are because they have the same …………………
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?
Study the extract of the Periodic Table given below and answer the questions that follow. Give the alphabet corresponding to the element in question. DO NOT repeat an element. 
The ion of which element will migrate towards the cathode during electrolysis?
What is meant by periodicity of elements?
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
How many elements are there in period 2?
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
Use the letters only written in the Periodic Table given below to answer the questions that follow:
(a) State the number of valence electrons in the atom J.(b) Which element shown forms ions with a single negative charge?
(c) Which Metallic element is more reactive than R?
(d) Which element has its electrons arranged in four shells?
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 |
Place the three elements fluorine, beryllium and nitrogen in the order of increasing electronegativity.
With reference to the variation of properties in the Periodic table, which of the following is generally true?
Write the electronic configuration of element 17T35.
- What is the group number of T?
- What is the period number of T?
- How many valence electrons are there in an atom of T?
- What is the valency of T?
- Is it a metal or non-metal?
- State number of protons and neutrons in T.
An element belongs to the third period and Group IIIA (13) of the periodic table. State: the name of the element.
Name and state the following with reference to the elements of the first three periods of the periodic table.
Metalloid in Period 3.
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
The similarities in the properties of a group of elements are because they have the same ______.
Name or state following with reference to the elements of the first three periods of the periodic table.
A metalloid in period 2 and in period 3.
Name or state following with reference to the element of the first three periods of the periodic table.
A non-metal in period 2 which is tetravalent.
Select the correct answer from the options given below.
It is a period having elements from atomic no. 11 to 18.
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 |
Which of the following would weigh the least?
(Atomic masses C = 12, 0 = 16, Na = 23)
