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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 questions.
i. What is the atomic number of this element?
ii. What is the valency of this element?
iii. What is the group of this element?
iv. To which period does this element belong?
v. With which of the following elements would this element resemble?
`_7N , _4Be , _18Ar , _17CL`
An element has its electron configuration as 2, 8, 2. Now answer the following question.
What is the atomic number of this element?
An element has its electron configuration as 2, 8, 2. Now answer the following question.
What is the group of this element?
Find the odd one out and give its explanation.
Write the name of noble gas having 2 electrons in its valence shell.
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 |
| 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 elements lithium and beryllium are in the same period because their valencies are similar.
Write scientific reason.
Boron and oxygen elements are placed in the second period in periodic table.
In group 2, beryllium and calcium elements, calcium is more electropositive element than beryllium.
Complete the following chart.
| Shell | n | 2n2 | Electron holding capacity |
| K | ______ | 2 × 12 | 2 |
| L | 2 | ______ | 8 |
| ______ | 3 | 2 × 32 | 18 |
| N | 4 | 2 × 42 | ______ |
Distinguish between:
Group - Period
Observe the given chart and answer the questions given below.
| Element | A | B | C | D |
| Electronic configuration | 2, 1 | 2, 8 | 2, 8, 1 | 2, 8, 8 |
- Which elements are in the same row?
- Which elements have the same column?
- Which elements are in the 18th column?
- Which element is more reactive among A and C?
- Which of the following elements A or B will form compounds?
XY compound is formed by X (Atomic number 11) and Y (Atomic number 17), then answer the questions given below.
- Determine the position of the element X and Y periodic table.
- X and Y belongs to which of the following: metals, nonmetals or metalloids?
- From which block the elements X and Y are?
- Determine the electronic configuration and valency of these elements.
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.
