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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
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?
The atomic numbers of three elements A, B and C are 12, 18 and 20 respectively. State, giving reason, which two elements will show similar properties.
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
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 many groups and periods are there in the modern periodic table?
Write the number of horizontal rows in the modern periodic table. What are these rows called?
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.
How does the number of valence electrons vary on moving from left or right in the second period of the periodic table?
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Fill in the blank in the following statement:
The tendency to gain an electron ............... on moving down in a group of the periodic table.
An element X belongs to group 2 and another element Y belongs to group 15 of the periodic table:
(a) What is the number of valence electron in X?
(b) What is the valency of X?
(c) What is the number of valence electrons in Y?
(d) What is the valency of Y?
Explain how you have arrived at your answers.
How do atomic structures (electron arrangements) change in a period with increase in atomic numbers from left to right?
In which part of a group would you separately expect the elements to have the greatest metallic character
The elements A, B, C, D and E have atomic numbers 9, 11, 17, 12 and 13 respectively. The pair of elements which belongs to the same group of the periodic table is:
(a) A and B
(b) B and D
(c) A and C
(d) D and E
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
Chorine in the periodic table is surrounded by the elements with atomic number 9, 16, 18 and 35.
Which of these have physical and chemical properties resembling chlorine.
Write two reasons responsible for late discovery of noble gases ?
An element 'M' has atomic number 11.
(a) Write its electronic configuration.
(b) State the group to which 'M' belongs.
(c) Is 'M' a metal or a non-metal.
(d) Write the formula of its chloride.
How do you calculate the possible valency of an element from the electronic configuration of its atoms?
Arrange the following in increasing order of property indicated
SiO2, P2O5, SO3, Cl2O7 (acidic nature)
What is meant by a group in the periodic table?
In the above table, H does not represent hydrogen.Some elements are given in their own symbol and position in the periodic table while others are shown with a letter. With refrence to the table answer the following questions.
1. Identify the most electronegative element.
2. Identify the most reactive element of Group I.
3. Identify the element from Period 3 with least atomic size.
4. How many valence electrons are present in Q?
5. Which element from group 2 would have the least ionisation energy?
6. Identify the noble gas of the fourth period.
7. In the compound between A and H, what type of bond would be formed and give its molecular formula.
Choose the most appropriate answer from the following list of oxides which fit the description.
An oxide which dissolves in water forming an acid.
Arrange the following as per instruction given in the bracket.
Cs, Na, Li, K, Rb (increasing metallic character)
Arrange the following as per instruction given in the bracket.
K, Pb, Ca, Zn (increasing reactivity)
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?
With reference to the variation of properties in the Periodic table, which of the following is generally true?
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.
Valency of elements in Group 14 and 15.
(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.
State the property trends in general of elements on moving from left to right in a period of the periodic table.
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.
Electron Affinity is maximum in ______.
Chlorine in the Periodic Table is surrounded by the elements with atomic number 9, 16, 18 and 35.
Which of these have Physical and Chemical properties resembling chlorine?
There are three elements E, F, G with atomic numbers 19, 8 and 17 respectively.
Classify the above elements as metals and non-metals.
