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Question
Answer the following question:
State the four blocks of the modern periodic table based on the electronic configuration of elements.
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Solution
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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RELATED QUESTIONS
Study the following table in which positions of six elements A, B, C, D, E and F are shown as they are in the modern periodic table:
|
Group→
Period↓ |
1
|
2
|
3-12
|
13
|
14
|
15
|
16
|
17
|
18
|
| 2 | A | B | C | ||||||
| 3 | D | E | F |
On the basis of the above table, answer the following questions:-
(i) Name the element which forms only covalent compounds.
(ii) Name the element which is a metal with valency three.
(iii) Name the element which is a non-metal with valency three.
(iv) Out of D and E, which is bigger in size and why?
(v) Write the common name for the family to which the elements C and F belong.
The elements Be, Mg and Ca each having two electrons in their outermost shells are in periods 2, 3, and 4 respectively of the modern periodic table. Answer the following questions, giving justification in each case:-
(i) Write the group to which these elements belong.
(ii) Name the least reactive element.
(iii) Name the element having largest atomic radius.
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
Name the element that has two shells, both of which are completely filled with electrons.
Classify the following elements into metals, non-metals and metalliods
As, C, Hg, Mg, S, Si
Choose the most appropriate answer of the following:
Which of the following would weigh the least?
(A) 2-gram atoms of Nitrogen.
(B) 1mole of Silver
(C) 22.4 liters of oxygen gas at 1 atmospheric pressure and 273K
(D) 6.02 x 1023 atoms of carbon.
[Atomic masses: Ag=108, N=14, O=16, C=12]
How do atomic structures (electron arrangements) change in a period with increase in atomic numbers from left to right?
How does Chemical reactivity of elements change on going from left to right in a period of the periodic table?
Give example in support of your answer.
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 tendency to gain electrons change as we go down in group 17 of the periodic table? Why does it change this way?
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
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 is the valence shell for the elements of second period of the modern periodic table?
(a) M shell
(b) K shell
(c) L shell
(d) N shell
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?
An element A has atomic number 14. To which period does this element belong and how many elements are there in this period.
How does the number of:
valence electrons and
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) ?
Which element has:
twice as many electrons in its second shell as in its first shell?
What is the common feature of the electronic configuration of the elements at the end of period 2, and period 3?
What is modern periodic law?
Fill in the blank
Most electropositive elements belong to ______ group.
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
Arrange the following in increasing order of property indicated
SiO2, P2O5, SO3, Cl2O7 (acidic nature)
'In a group, the atomic radii increase with increasing period number', explain this statement and justify it with reference to group 17.
Select the correct answer
Identify the metalloid
Arrange the following in order of increasing radii:
N, O, P
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 |
Which one of the above elements belongs to the halogen series?
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 is larger in size (i) D or E (ii) B or C
State the nature of compounds formed when group 17 elements combine with (i) metals (ii) non-metals.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Oxide of first group elements.
What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 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.
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 metal in period 2 having electronic configuration 2, 1?
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 ________.
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)
