Advertisements
Advertisements
Question
Write a scientific reason.
Boron and oxygen elements are placed in the second period in periodic table.
Advertisements
Solution
- Electronic configuration of boron is (2, 3). The electronic configuration of oxygen is (2, 6).
- Both boron and oxygen have electrons in the two shells, K and L.
- The elements with the same number of shells occupied by electrons belong to the same period.
Hence, boron and oxygen elements are placed in the second period in the periodic table.
APPEARS IN
RELATED QUESTIONS
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.
1H, 7N, 20Ca, 16S, 4Be, 18Ar Which of these elements belong to the second group?
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 group of this element?
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.
Answer the following question in one sentence.
Write the name of the noble gas having 2 electrons in its valence shell.
The number of electrons in the outermost shell of an atom determines the ______.
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.
Right or wrong sentence.
The valency of the elements in group 2 is 1.
Right or wrong sentence.
The elements lithium and beryllium are in the same period because their valencies are similar.
Write a scientific reason.
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 |
Find the period in which these elements can be placed.
4Be, 17Cl, 2He, 13Al
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.
- Which type of elements X and Y are metals, nonmetals or metalloids?
- From which block the elements X and Y are?
- Determine the electronic configuration and valency of these elements.
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.
