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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
Two elements ‘P’ and ‘Q’ belong to the same period of the modern periodic table and are in Group 1 and Group 2, respectively. Compare their following characteristics in tabular form:-
(a) The number of electrons in their atoms
(b) The sizes of their atoms
(c) Their metallic character
(d) Their tendencies to lose electrons
(e) The formula of their oxides
(f) The formula of their chlorides
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?
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
List any two properties of the elements belonging to the first group of 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.
Write the number of horizontal rows in the modern periodic table. What are these rows called?
Name the element that has two shells, both of which are completely filled with electrons.
Differentiate between Normal elements and Transition elements.
What happens to the metallic character of the elements as we go down in a group of the periodic table?
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
The atomic number of an element is 20. In modern periodic table, this element is placed:
(a) 2nd period
(b) 4th period
(c) 3rd period
(d) 1st period
Which of the following element would lose an electron easily?
(a) Mg
(b) Na
(c) K
(d) Ca
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?
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
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
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
What do you understand by orbits?
Why are noble gases placed in a separate group?
An element X belong to 4th period and 17th group, state.
name of the element.
Fill in the blank:
on moving from right to left in the second period, the number of valence electrons……….
An element X belong to 3rd periods and group II of the periodic table state:
name of the element,
name the elements in period 1.
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.
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. 
Which is an inert gas?
What is meant by periodicity of elements?
Select the correct answer
Most reactive character among the elements given below is found in
The following table represents the first period of the modern periodic table. Study the table and answer the questions that follow:
- Write the formula of the sulphate of the element with atomic number 13.
- What type of bonding will be present in the oxide of the element with atomic number 1?
- Which feature of the atomic structure accounts for the similarities in the chemical properties of the elements in group VIIA of the periodic table?
- Name the element which has the highest ionization potential.
- How many electrons are present in the valence shell of the element with atomic number 18?
- What is the name given to the energy released, when an atom in its isolated gaseous state accepts an electron to form an anion?
- What is the electronic configuration of the element in the third period which gains one electron to become an anion?
- Fill in the blanks:
The atomic size ______ as we move from left to right across the period, because the ______ increases, but the ______ remains the same.
The following questions refer to the Periodic Table.
Name the first and last element in period 2.
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 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 |
|
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E |
State which is most reactive (i) metal (ii) non-metal
An element belongs to the third period and Group IIIA (13) of the periodic table. State: the number of valence electrons,
Name and state the following with reference to the elements of the first three periods of the periodic table.
Alkaline earth metal in period 3.
Name the elements in Period 1.
State the property trends in general of elements on moving down in a group of the periodic table.
Select the correct answer from the options given below.
It is a period having elements from atomic no. 11 to 18.
