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प्रश्न
Find the odd one out and give its explanation.
पर्याय
Potassium
Magnesium
Calcium
Beryllium
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उत्तर
Potassium
Explanation:
Magnesium, calcium, and beryllium all belong to Group 2 of the periodic table, collectively known as the alkaline earth metals. Potassium, however, belongs to Group 1, known as the alkali metals, which makes it much more reactive and gives it a different valency compared to the other three.
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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.
11Na, 15P, 17Cl, 14Si, 12Mg Which of these has largest atoms?
Write the scientific reason.
The third period contains only eight elements even though the electron capacity of the third shell is 18
An element has its electron configuration as 2, 8, 2. Now answer the following question.
What is the atomic number of this element?
Answer the following question in one sentence.
Write the name of the noble gas having 2 electrons in its valence shell.
Answer the following question in one sentence.
Write the name of an element having electronic configuration 2,8,2.
Answer the following question in one sentence.
What determines the chemical reactivity of elements?
Match the columns.
| Column A Electronic configuration |
Column B Valency |
| 1) 2, 2 | a) 1 |
| 2) 2, 8, 1 | b) 2 |
| 3) 2, 5 | c) 3 |
| d) 5 |
Write the name.
The element having stable electron configuration from the third period.
Write the name.
The group of elements having electronic configuration 2, 2.
Write a scientific reason.
Boron and oxygen elements are placed in the second period in periodic table.
Find the period in which these elements can be placed.
4Be, 17Cl, 2He, 13Al
Electronic configuration of element A is 2,8,1. Answer the following questions based on this information.
- What is the atomic number of element A?
- Find the group to which this element belongs.
Identify periods of elements and blocks of elements from given electronic configuration.
- 2, 8, 2
- 2, 8, 7
- 2, 1
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?
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.
An element has its electron configuration as 2, 8, 1. Now answer the following questions:
- What is the atomic number of this element?
- What is the group of this element?
- To which period does this element belong?
