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प्रश्न
Which one of the following does not increase while moving down the group of the periodic table?
पर्याय
Atomic radius
Metallic character
Valency
Number of shells
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उत्तर
Valency
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संबंधित प्रश्न
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.
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?
Write the number of periods the Modern Periodic Table has. State the changes in valency and metallic character of elements as we move from left to right in a period. Also state the changes, if any, in the valency and atomic size of elements as we move down a group.
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
What is meant by 'group' in the modern periodic table? How do the following change on moving from top to bottom in a group?
(i) Number of valence electrons
(ii) Number of occupied shells
(iii) Size of atoms
(iv) Metallic character of element
(v) Effective nuclear charge experienced by valence electrons
How do the valency and the atomic size of the elements vary while going from left to right along a period in the modern periodic table?
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.
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 ?
Name the element that has two shells, both of which are completely filled with electrons.
Which element has a total of three shells, with four electrons in its valence shell?
An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is ______.
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
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]
Calculate the mass of Calcium that will contain the same number of the atom as are present in 3.2 gm of Sulphur.
[Atomic masses: S=32, Ca=40]
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
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.
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.
Given alongside is a part of the periodic table. As we move vertically downward from Li to Fr:
| Li | Be |
| Na | |
| K | |
| Rb | |
| Cs | |
| Fr | Ra |
What happens to their metallic character?
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
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?
Why sodium element of group 1 and chlorine element of group 17 both have valency 1?
What do you understand by orbits?
An element X belong to 4th period and 17th group, state.
no of valence electrons in it
An element barium has atomic number 56. Look up its position in the periodic table and answer the following question.
Is it more or less reactive than calcium?
Complete the following sentences.
The properties of the elements are a periodic function of their …………… (atomic number, mass number, reative atomic mass).
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?
How many groups and periods are there in the modern periodic table?
Fill in the blank
Oxidising property ________from fluroine to iodine because the power to accpet electron decreases.
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
(a) To which period do these elements belong?
(b) One element of this period is missing. Which is the missing element and where should it be placed?
(c) Place the three elements, fluorine, beryllium and nitrogen, in the order of increasing electro negativity.
(d) Which one of the above elements belongs to the halogen series?
An element belongs to the third period and Group IIIA (13) of the periodic table. State: the valency,
An element belongs to the third period and Group IIIA (13) of the periodic table. State: if it is a metal or non-metal?
An element A has 2 electrons in its fourth shell. State:
its valency
An element A has 2 electrons in its fourth shell. State:
is it an oxidising or reducing agent
What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3?
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.
