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प्रश्न
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
19K, 3Li, 11Na, 4Be Which of these atoms has smallest atomic radius?
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उत्तर
19K, 3Li, 11Na, 4Be
Electronic configuration of the following elements is:
19K = 2,8,8,1
3Li = 2,1
11Na = 2,8,1
4Be = 2,2
4Be has smallest atomic radius because 19K, 3Li, 11Na are present in same group 1 but Be is present in group 2. According to the trend, as we move from left to right atomic size of an atoms decreases. Due to large positive charge on the nucleus, the electrons are pulled closer to the nucleus and the size of atom decreases.
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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?
Which pair of atomic numbers represents elements in the same group?
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
Answer the following question in one sentence.
What determines the chemical reactivity of elements?
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 |
| 1) Alkaline earth metals | a) Group 18 |
| 2) Alkali metals | b) Group 17 |
| 3) Halogen | c) Group 2 |
| 4) Noble gas | d) Group 1 |
| e) Group 14 |
The number of electrons in the outermost shell of an atom determines the ______.
Write the name.
Highest electropositive element
Write the name.
The group of elements having electronic configuration 2, 2.
Right or wrong sentence.
The elements lithium and beryllium are in the same period because their valencies are similar.
Beryllium and calcium are alkaline earth metals.
Write a scientific reason.
Boron and oxygen elements are placed in the second period in periodic table.
Write a scientific reason.
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
Make a chart which shows the name of the element, valency, atomic number, electronic configuration in the 2nd row of the modern periodic table and arrange these elements in ascending order of atomic mass.
What is the electronic configuration of K19?
