A: The position of d-block elements is in between the s-block and p-block elements in the periodic table. These d-block elements are called transition elements because they exhibit transitional behaviour between s-block and p-block elements.

Their properties are transitional between highly reactive metallic elements of s-block which are typically ionic compounds and the elements of p-block which are largely covalent.

An oxidation number is a number that is assigned to an atom in a substance. The oxidation number could be positive, negative, or zero, and it indicates if electrons are lost or gained.

In other words, the oxidation number is a number that helps us keep track of electrons in an atom.

Here, the oxidation number of calcium is +2 and the oxidation number of oxygen is -2.

If the oxidation number is positive, then this means that the atom loses electrons, and if it is negative, it means the atom gains electrons. If it is zero, then the atom neither gains nor loses electrons.

In chemistry, hybridisation (or hybridization) is the concept of mixing atomic orbitals into new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds in valence bond theory.

clear your basic concepts of class 9th and 10th.

In chemistry isomerization (also isomerisation) is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms have a different arrangement

The ionization energy (IE) is qualitatively defined as the amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation.

 Lewis de-Broglie proposed that matter has dual characteristic just like radiation. His concept about the dual nature of matter was based on the following observations:-

(a) The whole universe is composed of matter and electromagnetic radiations. Since both are forms of energy so can be transformed into each other.

(b) The matter loves symmetry. As the radiation has dual nature, matter should also possess dual character.

According to the de Broglie concept of matter waves, the matter has dual nature. It means when the matter is moving it shows the wave properties (like interference, diffraction etc.) are associated with it and when it is in the state of rest then it shows particle properties.

Thus the matter has dual nature. The waves associated with moving particles are matter waves or de-Broglie waves.

WAVELENGTH OF DE-BROGLIE WAVES Consider a photon whose energy is given by E=hυ=hc/λ – – (1)

 If a photon possesses mass (rest mass is zero), then according to the theory of relatively ,its energy is given by E=mc2 – – (2)

From (1) and (2) ,

we have Mass of photon m= h/cλ Therefore Momentum of photon P=mc=hc/cλ=h/λ – – (3)

Or

λ = h/p If instead of a photon, we consider a material particle of mass m moving with velocity v,then the momentum of the particle ,p=mv. Therefore, the wavelength of the wave associated with this moving particle is given by: h/mv – Or λ = h/p (But here p = mv) .

(4) This wavelength is called DE-Broglie wavelength

The answer is 2. In ozone molecule there are two possible resonating structure in which double and single bond exist between oxygen atoms, hence the bond order will be average of both that is 1.5.

• Chain isomerism relates to molecules with the same molecular formula but different carbon skeleton.
• Positional isomerism relates to molecules with the same carbon skeleton but functional groups in different positions.

A logarithm is the power to which a number must be raised in order to get some other number .

For example, the base ten logarithm of 100 is 2, because ten raised to the power of two is 100: log 100 = 2.

Orbitals which are half filled do certainly have unpaired electron or electrons with all the spins oriented in one direction. So certainly they are unstable. Orbitals which are filled fully have all the electrons paired. Hence they are highly stable.

Two electrons in an orbital create opposite electric and magnetic fields due to their spin. Now if a third electron enters it spin would match with any one of the two electrons of orbit, so repulsion will occur and third electron will not enter into the orbit.