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प्रश्न
Atomic number of metal ‚A‛ is 11, while atomic number of metal ‚B‛ is 20. Which of them will be more reactive? Write the chemical reaction of dilute HCl with metal ‚A‛.
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उत्तर
Metal ‘A’ is more reactive than metal ‘B’.
Atomic number of metal ‘A’ is 11, hence it is Na.
`2Na + 2HCI → 2NaCI(aq) + H_2 (g) `
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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
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
Define the term : Atomic size
Which element has the electronic configuration 2, 8, 2?
Which element has twice as many electrons in its second shell as in its first shell?
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.
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
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?
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
Name the non-metals present in period 2 and metals in period 3.
Name the element of lower nuclear charge out of Be and Mg.
Four elements P, Q, R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valences. Write the molecular formula of the compound formed when P and S combine.
An element 'M' has atomic number 12.
(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.
K, Pb, Ca, Zn (In the increasing order of the reactivity)
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?
Fill in the blank
Most electropositive elements belong to ______ group.
Arrange the following in increasing order of property indicated
SiO2, P2O5, SO3, Cl2O7 (acidic nature)
Select the correct answer
Number of shells in potassium are
What is meant by a group in the periodic table?
Parts (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non metallic character of the elements:
(a) Decreases
(b) Increases
(c) Remains the same
(d) Depends on the period
(ii) The electro negativity
(a) Depends on the number of valence electrons
(b) Remains the same
(c) Decreases
(d) Increases
(iii) The ionization potential
(a) Goes up and down
(b) Decreases
(c) Increases
(d) Remains the same
(iv) The atomic size
(a) Decreases
(b) Increases
(c) Remains the same
(d) Sometimes increases and sometimes decreases
(v) The electron affinity of the elements in groups 1 to 7:
(a) Goes up and down
(b) Decreases and then increases
(c) Increases
(d) decreases
Choose the most appropriate answer from the following list of oxides which fit the description.
An oxide which dissolves in water forming an acid.
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.
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 type of ion will be formed by elements A, B, and C.
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
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: the name of the element.
Name and state the following with reference to the elements of the first three periods of the periodic table.
Non-metallic elements present in Period 3 of Groups 15 and 16.
An element A has 2 electrons in its fourth shell. State:
its valency
What is meant by a Group in the Periodic Table?
Name or state following with reference to the element of the first three periods of the periodic table.
A non-metal in period 2 having electronic configuration 2, 6.
Name or state following with reference to the element of the first three periods of the periodic table.
A metal in period 3 having valency 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.
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.
