Duduli

With hydrogen atom as the positive end of the dipole, if bonds arise as a result of electrostatic attraction between atoms, it is known as hydrogen bonding.

“Isoelectronic molecular species (I.e species having same number of atoms and same number of total valence electrons) have similar molecular orbitals and similar molecular structure.”

It is defined as the number of covalent bonds in a molecule.Bond order is equal to one half of the difference between the number of electrons in the bonding (Nb) and anti-bonding (Na) molecular orbitals.   I.e Bond order =1/2 (Nb-Na)

Answer:- Elements present in the second and third periods show diagonal relationship with each other, i.e, they resemble each other.For example, Li, Be and B resemble Mg, Al and Si respectively.

Answer:- It is the property by virtue of which an element may exist in two or more forms which have different physical properties but almost similar chemical properties.

Answer:- In 1985, it was found that action of laser beams on graphite produced a spherical molecule made of 60 carbon atoms covalently bonded together.It is now called Buckminster fullerene.It is named after the American architect Buckminster fuller, who designed domed structures with the same geometry.

Answer:- Those elements (except He) in which last electron enters into the s-subshell of the outermost main energy level, are called S-block element.

Answer:- It is defined as the number of parts of calcium carbonate or magnesium carbonate equivalent to various calcium and magnesium salts present in million parts (10⁶parts) of water by mass.It is expressed in ppm(parts per million).

Answer:- It is the most common method of expressing concentration of hydrogen peroxide solution.In this method, the concentration is expressed in terms of the volume of oxygen, which is a solution of hydrogen peroxide gives on decomposition.

Answer:- It is due to the presence of chlorides and sulphides of calcium, magnesium and iron in water.This type of hardness of water is also known as non-carbonate hardness.It is named permanent hardness because such a hardness cannot be removed by simply boiling the water.

Answer:- It is due to the presence of bicarbonates of calcium, magnesium and iron dissolved in water.This type of hardness is also known as carbonate hardness.It is named temporary hardness because it can be removed by simply boiling the water.

Answer:- Softening of water is the process of removal of dissolved salts i.e, chlorides  bicarbonates and sulphates of calcium and magnesium.

Answer:- It is due to the presence of bicarbonates, sulphates and chlorides of calcium and magnesium in it.These salts get dissolved in it as it passes through the rocks or ground.

Answer:- Water which does not readily produce lather with soap solution is known as hard water.Examples of hard water are sea water, river water, well and tap water

Answer:- Water which readily produces lather with soap solution (in alcohol) is known as soft water.Examples of soft water are distilled water and rain water.

Answer:- The probability of finding an electron at a point in an atom is proportional to the square of the orbital wave function.Thus, is called probability density.

Answer:- Molecular orbitals may be defined as the regions in space in which an electron is most likely to be found.The molecular orbital with lower energy is called bonding molecular orbital (more stable).The molecular orbital with higher energy is called anti-bonding molecular orbital.

Answer:- This type of bonding occurs between atoms in a compound in which one atom has lone pair of electron and the other has vacant orbital placed adjacent to each other.

Answer:- Hybridization is the concept of intermixing of the orbitals of an atom having nearly the same energy to give exactly equivalent orbitals with same energy, identical shapes and symmetrical orientations in space.

Answer:- An acid reacts with a base to produce a salt and water.Hydrogen from the acid combines with hydroxide ion from the base to form water molecules.