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प्रश्न
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?
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उत्तर
- Li > Be > B > C > N > O
- 2nd period
- Yes, this elemental arrangement resembles the era of the contemporary periodic table mentioned above. The positive charge on the nucleus grows one unit at a time as we move from left to right over a period of time, but when electrons are added to the same orbit, the pull away from the nucleus increases, reducing the size of the atom.
- Li is the biggest atom oxygen is the smallest atom
- While going from left to right within a period atomic radius decreases due to an increase in effective nuclear charge.
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संबंधित प्रश्न
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
How many groups and periods are there in the modern periodic table?
Write the atomic numbers of two elements 'X' and 'Y' having electronic configuration 2, 8, 2 and 2, 8, 6 respectively.
Define the term : Atomic size
Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)
Match the atomic number 2, 4, 8, 15 and 19 with each of the following
1) A solid non metal belonging to the third period.
2) A metal of valency 1.
3) A gaseous element with valency 2.
4) An element belonging to Group 2
5) A rare gas.
Use the letters only written in the Periodic Table given below to answer the questions that Follow :
1) State the number of valence electrons in atom J.
2) Which element shown forms ions with a single negative charge?
3)Which metallic element is more reactive than R?
4) Which element has its electrons arranged in four shells?
Differentiate between Normal elements and Transition elements.
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
How does the number of valence electrons vary on moving from left or right in the first period of the periodic table?
Name the element which is in seventeenth group and second period.
How do electronic configurations of elements change in second period of periodic table with increase in atomic numbers?
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 ...............
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.
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?
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
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
In each of the following pair, choose the atom having the bigger size:
(a) Mg (At. No.12) or Cl (At. No.17)
What do you understand by orbits?
What is its atomic number?
An element X belong to 4th period and 17th group, state.
Write the formula of the compound formed when it reacts with `(27)/(13) y `
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.
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.
Calculate the valency of element X whose atomic number is 9.
State whether the following statement is true or false
Similar electronic configuration is repeated after intervals of 2, 8, 8, 18 and 32.
Select the correct answer
Number of shells in potassium are
What is the common feature of electronic configurations of the elements at the end of period 2 and period 3?
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 |
To which period do these elements belong?
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 metals, non-metals, and noble gas in this table.
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
Going across a period left to right, atomic size _____.
Moving left to right in the second period, the number of valence electrons _____.
(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.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
Supply the missing word from those in bracket:
If an element has one electron in its outermost energy level [shell] then it is likely to be _______.
Give a reason for the following:
A transition from metallic to non-metallic elements is seen on moving from left to right in a period of the periodic table.
State the following:
The group which contains highly electropositive metals including sodium.
