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प्रश्न
Write scientific reason.
Boron and oxygen elements are placed in the second period in periodic table.
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उत्तर
- Electronic configuration of boron is (2, 3). Electronic configuration of oxygen is (2, 6).
- Both boron and oxygen have electrons in the two shells, K and L.
- The elements with the same number of shells occupied by electrons belong to the same period.
Hence, boron and oxygen elements are placed in the second period in the periodic table.
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संबंधित प्रश्न
An element has its electron configuration as 2, 8, 2. Now answer the following question.
a. What is the atomic number of this element?
b. What is the group of this element?
c. To which period does this element belong?
d. With which of the following elements would this element resemble? (Atomic numbers are given in the brackets)
N(7), Be(4), Ar(18), Cl(17)
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
7N, 6C, 8O, 5B, 13Al Which is the most electronegative element among these?
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
6C, 3Li, 9F, 7N, 8O Which of the above elements has the highest nonmetallic character?
Write the scientific reason.
The third period contains only eight elements even though the electron capacity of the third shell is 18
Which of this element belong to the period 3? Write their electronic configuration
`3^(Li) , 14^(Si) , 2^(He) , 15^(P)`
Which pair of atomic numbers represents elements in the same group?
Find the odd one out and give its explanation.
Write the name of an element having electronic configuration 2,8,2.
Match the columns.
| Column A | Column B |
| 1) s -block | a) Lanthanides and actinides |
| 2) p -block | b) Group 3 to 12 |
| 3) d -block | c) Group 1, 2 |
| 4) f -block | d) Group 13 to 18 |
| e) Zero group |
Match the columns.
| Column A | Column B |
| Electronic configuration |
Valency |
| 1) 2, 2 | a) 1 |
| 2) 2, 8, 1 | b) 2 |
| 3) 2, 5 | c) 3 |
| d) 5 |
Write the name.
The group of elements having electronic configuration 2, 2.
The valency of the elements in group 2 is 1.
The elements lithium and beryllium are in the same period because their valencies are similar.
Beryllium and calcium are alkaline earth metals.
Write an Explanation.
Group
In group 2, beryllium and calcium elements, calcium is more electropositive element than beryllium.
Find the period in which these elements can be placed.
4Be, 17Cl, 2He, 13Al
Write name of elements, symbol, atomic number, electronic configuration of second period in modern periodic table?
Identify periods of elements and blocks of elements from given electronic configuration?
- 2, 8, 2
- 2, 8, 7
- 2, 1
Observe the periodic table given below and write the answers of the questions.
- Write the name and valencies of the elements in 3rd row.
- Classify the elements in this row as metal, nonmetal and metalloids.
- Which block does nonmetals belong to?
- Write name of any two metalloid elements.
