Advertisements
Advertisements
प्रश्न
Fill in the blank and rewrite the completed statement:
________ group in the periodic table contains elements that are all gases at room temperature.
Advertisements
उत्तर
The 18th group in the periodic table contains elements that are all gases at room temperature.
APPEARS IN
संबंधित प्रश्न
The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.
- Calculate the average atomic mass of elements A and C.
- Compare the average atomic mass with atomic mass of B.
- What could the elements A, B and C be?
Taking the example of an element of atomic number 16, explain how the electronic configuration of the atom of an element relates to its position in the modern periodic table and how valency of an element is calculated on the basis of its atomic number.
Na, Mg and Al are the elements of the same period of Modern Periodic Table having, one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each case.
Which element has a total of two shells, with three electrons in its valence shell?
In the following set of elements, one element does not belong to the set. Select this element and state why it does not belong:
Oxygen, Nitrogen, Carbon, Chlorine, Fluorine
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?
How does the tendency to gain electrons change as we go down in group 17 of the periodic table? Why does it change this way?
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
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?
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
Which one of the following does not increase while moving down the group of the periodic table?
Why are noble gases placed in a separate group?
Name two elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?
State the trends in physical properties on moving down the group. Give an example to illustrate.
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?
An element X belong to 3rd periods and group II of the periodic table state:
the valency,
Name the element which has the electronic configuration 2, 8, 3?
Name the element in period 3 which does not form oxide.
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?
How many groups and periods are there in the modern periodic table?
What is meant by periodicity of elements?
Fill in the blank
Oxidising property ________from fluroine to iodine because the power to accpet electron decreases.
Give the number of the group and the period of elements having three shells with three electrons in valence shell.
In the above table, H does not represent hydrogen.Some elements are given in their own symbol and position in the periodic table while others are shown with a letter. With refrence to the table answer the following questions.
1. Identify the most electronegative element.
2. Identify the most reactive element of Group I.
3. Identify the element from Period 3 with least atomic size.
4. How many valence electrons are present in Q?
5. Which element from group 2 would have the least ionisation energy?
6. Identify the noble gas of the fourth period.
7. In the compound between A and H, what type of bond would be formed and give its molecular formula.
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 |
To which period do these elements belong?
An element A has 2 electrons in its fourth shell. State:
is it an oxidising or reducing agent
(a) Fill in the blanks and rewrite the completed statements:
(i) ________ group in the periodic table contains elements that are all gases at room temperature.
(ii) Very fine particles mainly scatter ______ light.
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.
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 formula of the hydroxide of the element having electronic configuration 2, 8, 2.
Select the correct answer from the options given below.
It is a metal in period 2 having electronic configuration 2, 1?
Electron Affinity is maximum in ______.
There are three elements E, F, G with atomic numbers 19, 8 and 17 respectively.
Classify the above elements as metals and non-metals.
