Anamolous Behaviour of Boron

Q.

Boron cannot form which one of the following anions?

1. 

2. 

3. 

4. 

Q.

The d-block elements consists mostly of

1. Monovalent metals

2. All non-metals

3. Elements which generally form stoichiometric metal oxide

4. Many metals with catalytic properties

Q.

Read the following and select one the correct answer.

Statement I: Boron always forms covalent bond

Statement II: The small size of $B^{3+}$ favours formation of covalent bond

1. Statement I and Statement II are both correct. Statement II correctly explains Statement I

2. Statement I and Statement II are both correct. Statement II does not explain Statement I

3. Statement II is correct and Statement I is wrong

4. Statement I is correct and Statement II is wrong

Q. 8. An excited hydrogen atom when comes directly to the ground state emits a photoelectron with de broglie wavelength 4.09 Armstrong. If work function of metal is 3.75ev find out the no of orbit of hydrogen atom in which electron was present initially.

Q. Which is the hardest element among alkaline earth metals

Q.

Be shows difference in properties as compared to rest of the members of its group because of:

1. Small size

2. High ionization enthalpy

3. Non availablilty of d orbitals

4. All the these

Q.

$Al{F}_3+B_2{O}_3$$\to$ ________ $+B{F}_3$

1. 

2. 

3. 

4. 

Q.

Why is the maximum covalence of B 4?

Q. How can you explain higher stability of $BC{l}_3$ as compared to $TlC{l}_3$?

Q. Solve this:
Q.(c) What is electronegativity? Explain why halogens possess highest electronegativity.

Q.

Which is more ionic SnCl₂ or SnCl4?

Q.

$H_{3}B{O}_3\stackrel{T_1}{⟶}\times \stackrel{T_2}{⟶}Y\stackrel{Redhot}{⟶}{B}_2{O}_3$

If $T_1$$<$$T_2$ then X and Y respectively are

1. X = Metaboric acid and Y = Tetraboric acid

2. X = Borax and Y = Metaboric acid

3. X = Tetraboric acid and Y = Borax

4. X = Tetraboric acid and Y = Metaboric acid

Q. Which of the following is/are anomaly(ies) of boron?

1. metallic nature
2. allotropy
3. +1 oxidation state
4. non-metallic nature

Q. The element with highest ionization enthalpy among the following is

Q. the 4th line of balmer series corresponds to the electronic transition between 2 orbis of the H atom