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प्रश्न
Fill in the blank and rewrite the completed statement:
________ group in the periodic table contains elements that are all gases at room temperature.
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उत्तर
The 18th group in the periodic table contains elements that are all gases at room temperature.
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संबंधित प्रश्न
An element 'X' has mass number 35 and number of neutrons 18. Write atomic number and electronic configuration of 'X'. Also write group number, period number and valency of 'X'.
How many groups and periods are there in the modern periodic table?
Write the number of vertical columns in the modern periodic table. What are these columns called?
Based on the group valency of elements state the formula lot the following giving justification for each :-
(i) Oxides of 1st group elements,
(ii) Halides of the elements of group 13, and
(iii) Compounds formed when an element of group 2 combines with, an element of group 16.
Fill in the blank in the following statement:
On going down in a group in the periodic table, the metallic character of elements ...............
For each of the following triads, name the element with the characteristics specified below:
| Elements | Least atomic radius | Chemically least reactive |
| (i) F, Cl, Br (ii) Li, Na, K |
.................... .................... |
.................... .................... |
The electronic configuration of the atom of an element X is 2, 8, 4. In modern periodic table, the element X is places in :
(a) 2nd group
(b) 4th group
(c) 14th group
(d) 8th group
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 | Ra |
What happens to the size of atoms?
Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?
An element which is an essential constituent of all organic compounds belongs to following group of modern periodic table:
(a) group 4
(b) group 14
(c) group 15
(d) group 16
Name two elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?
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 `
Complete the following sentences.
The properties of the elements are a periodic function of their …………… (atomic number, mass number, reative atomic mass).
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.
name the elements in period 1.
What is the common feature of the electronic configuration of the elements at the end of period 2, and period 3?
Calculate the valency of element X whose atomic number is 9.
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?
Select the correct answer
Number of shells in potassium are
Select the correct answer
Most reactive character among the elements given below is found in
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?
Write the electronic configuration of element 17T35.
- What is the group number of T?
- What is the period number of T?
- How many valence electrons are there in an atom of T?
- What is the valency of T?
- Is it a metal or non-metal?
- State number of protons and neutrons in T.
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.
Moving left to right in the second period, the number of valence electrons _____.
An element A has 2 electrons in its fourth shell. State:
position in the periodic table
An element A has 2 electrons in its fourth shell. State:
is it a metal or non-metal
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
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.
The position of certain elements in the Modern Periodic Table is shown below:
Using the above table answer the following questions giving reasons in each case :
(i) Which element will form only covalent compounds?
(ii) Which element is a non-metal with valency 2?
(iii) Which element is a metal with valency 2?
(iv) Out of H, C, and F which has the largest atomic size?
(v) To which family does H, C, and F belong?
Name the elements in Period 1.
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 _______.
Name or state following with reference to the elements of the first three periods of the periodic table.
The number of electron shells in elements of period 1, period 2, and period 3.
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.
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.
Fill in the blanks from the words A to F given below.
A: Decreases
B: Increases
C: Remains same
D: Increases by one
E: Electropositive
F: Electronegative
Down a group in the Modern Periodic Table.
No. of electron shells __________; No. of valence electrons ________; Electronegativity ________ Character of elements changes from _________ to ____________.
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
