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प्रश्न
उत्तर
Atomic size increases down the group
- The atomic numbers of the elements increase as we go down the group. Thus, the elements placed lower have more electrons.
- To accommodate these electrons new shells are added to the atom.
- These new shells take the outermost electrons farther from the nucleus causing atomic size (radius) to increase as we go down the group.
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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?
An element 'X' belong to 3rd period and group 13 of the Modern Periodic Table.
(a) Determine the valence electrons and the valency of 'X'.
(b) Molecular formula of the compound formed when 'X' reacts with an element 'Y' (atomic number = 8).
(c) Write the name and formula of the compound formed when 'X' combines with chlorine
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.
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 number of valence electrons vary on moving from left or right in the second period of the periodic table?
Rewrite the following statement after correction, if necessary:
Elements in the same period have equal valency
Fill in the blank in the following statement:
In going across a period (right to left) in periodic table, the atomic size of the atom ...............
How does Nature of oxides of elements change on going from left to right in a period of the periodic table?
Give examples in support of your answer.
Why do elements in the same group show similar properties but the elements in different groups show different properties?
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?
Where would you locate the element with electronic configuration 2, 8 in the modern periodic table?
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
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
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?
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 `
An element X belong to 3rd periods and group II of the periodic table state:
the valency,
Complete the following sentences.
The properties of the elements are a periodic function of their …………… (atomic number, mass number, reative atomic mass).
What is the common feature of the electronic configuration of the elements at the end of period 2, and period 3?
How can the valency of an element be determined if its electronic configuration is known?
Calculate the valency of element X whose atomic number is 9.
What is meant by periodicity of elements?
Fill in the blank
There are ______ groups and ______ periods in the modern form of periodic table.
Fill in the blank
Oxidising property ________from fluroine to iodine because the power to accpet electron decreases.
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
Name the elements in period 1.
The following questions refer to the Periodic Table.
Name the first and last element in period 2.
Atomic number of an element is 16. State
- the period to which it belongs
- the number of valence electrons
- whether it is a metal or non-metal
Give the number of the group and the period of elements having three shells with three electrons in valence shell.
Choose the correct answer from the choice given:
An element A belonging to Period 3 and Group II will have
Use the letters only written in the Periodic Table given below to answer the questions that follow:
(a) State the number of valence electrons in the atom J.(b) Which element shown forms ions with a single negative charge?
(c) Which Metallic element is more reactive than R?
(d) Which element has its electrons arranged in four shells?
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?
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?
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.
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.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
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?
