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प्रश्न
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.
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उत्तर
- The elements in the third period are Sodium, Magnesium, Aluminium, Silicon, Phosphorus, Sulphur, Chlorine and Argon. Their valencies are 1, 2, 3, 4, 3, 2, 1 and 0, respectively.
- Sodium (Na), Magnesium (Mg) and Aluminium (Al) are metals. Silicon (Si) is a metalloid. Phosphorus (P), Sulphur (S), Chlorine (Cl) and Argon (Ar) are nonmetals.
- Nonmetals belong to the p-block.
- Two metalloid elements: Silicon and Germanium.
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संबंधित प्रश्न
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
3Li, 14Si, 2He, 11Na, 15P Which of these elements belong to be period 3?
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
1H, 7N, 20Ca, 16S, 4Be, 18Ar Which of these elements belong to the second group?
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.
19K, 3Li, 11Na, 4Be Which of these atoms has smallest atomic radius?
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with an explanation.
13Al, 14Si, 11Na, 12Mg, 16S
Which of the above elements has the highest metallic character?
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`
Which of this element belong to the period 3? Write their electronic configuration
`3^(Li) , 14^(Si) , 2^(He) , 15^(P)`
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.
Which of the following elements would this element resemble?
(Atomic numbers are given in the brackets)
N(7), Be(4), Ar(18), Cl(17)
Which pair of atomic numbers represents elements in the same group?
Which among the following elements would lose an electron easily?
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
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 |
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 |
Right or wrong sentence.
The number of shields decreases as the calculation goes down from top to bottom.
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 |
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.
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?
