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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) and Chlorine (Cl) are nonmetals. Argon (Ar) is an inert gas element and is not classified as a metal, nonmetal or metalloid. - Nonmetals belong to p-block.
- Two metalloid elements: Silicon and Germanium.
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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.
19K, 3Li, 11Na, 4Be Which of these atoms has smallest atomic radius?
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.
To which period does this element belong?
Which among the following elements would lose an electron easily?
Find the odd one out and give its explanation.
Write the name of an element having electronic configuration 2,8,2.
What determines the chemical reactivity of elements?
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 |
Write the name.
Highest electropositive element
The valency of the elements in group 2 is 1.
Beryllium and calcium are alkaline earth metals.
The number of shells decreases in a group from top to bottom.
Write an Explanation.
Group
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.
Find the period in which these elements can be placed.
4Be, 17Cl, 2He, 13Al
Identify periods of elements and blocks of elements from given electronic configuration?
- 2, 8, 2
- 2, 8, 7
- 2, 1
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.
What is the electronic configuration of K19?
