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प्रश्न
Classify the following elements into metals, non-metals and metalliods
As, C, Hg, Mg, S, Si
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उत्तर
| Metals | Non-metals | Metalloids |
| Hg | C | Si |
| Mg | S | As |
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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?
Calcium is an element with atomic number 20. Stating reason, answer each of the following questions:-
(i) Is calcium a metal or a non-metal?
(ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19?
(iii) Write the formula of its oxide.
Name any two elements of group one and write their electronic configurations. What similarity do you observe in their electronic configurations? Write the formula of oxide of any of the aforesaid elements.
How many groups and periods are there in the modern periodic table?
How do the atomic size and metallic character of elements vary as we move?
- down a group and
- from left to right in a period
Write the number of horizontal rows in the modern periodic table. What are these rows called?
Match the atomic number 2, 4, 8, 15 and 19 with each of the following:
- A solid non-metal belonging to the third period.
- A metal of valency 1.
- A gaseous element with valency 2.
- An element belonging to Group 2.
- A rare gas.
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
Arrange the following elements in the increasing order of their metallic character:
Mg, Ca, K, Ga
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
Fill in the blank in the following statement:
On moving form right to left in the second period, the number of valency electrons ...............
Fill in the blank in the following statement:
On going down in a group in the periodic table, the metallic character of elements ...............
The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm; 104 pm and 143 pm respectively. Giving a reason, arrange these elements in the increasing order of atomic numbers in the period.
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?
What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?
Which of the following element would lose an electron easily?
(a) Mg
(b) Na
(c) K
(d) Ca
Which of the following element does not lose an electron easily?
(a) Na
(b) F
(c) Mg
(d) Al
The atomic numbers of the elements Na, Mg, K and Ca are 11, 12, 19 and 20 respectively. The element having the largest atomic radius is:
(a) Mg
(b) Na
(c) K
(d) Ca
Why sodium element of group 1 and chlorine element of group 17 both have valency 1?
State the trends in physical properties on moving down the group. Give an example to illustrate.
How does the number of:
valency vary on moving from left to right in the second period of the periodic table?
Name the element which has the electronic configuration 2, 8, 3?
An element 'X' (Atomic number – 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
Arrange the following according to the instruction given in the bracket:
K, Pb, Ca, Zn (in the increasing order of the reactivity).
Fill in the blank
Most electropositive elements belong to ______ group.
State whether the following statement is true or false
Similar electronic configuration is repeated after intervals of 2, 8, 8, 18 and 32.
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 |
One element of this period is missing. Which is the missing element and where should it be placed?
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
Fill in the blank and rewrite the completed statement:
________ group in the periodic table contains elements that are all gases at room temperature.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Compound formed when an element A of group 2 combines with an element B of group seventeen.
Name the period which is the shortest period of the periodic table.
Name or state following with reference to the element of the first three periods of the periodic table.
The valency of elements in group 1 [I–A].
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.
The valency of the element in period 3 having atomic number 17.
Which of the following would weigh the least?
(Atomic masses C = 12, 0 = 16, Na = 23)
