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non polar

Tetrachlorornethane is a molecule non polar.

The arrangement of eight electrons in the outermost shell of atom is called octet electron configuration. In Helium atom there is only one shell. The maximum number of electrons in the first shell is 2. Hence two-electron pattern system of Helium also stable.

1. Metallic crystals are an assemblage of positive ions immersed in a gas of free electrons. The free electrons are due to the ionisation of the valence electrons of the atom of the metal.

2. As the valence electrons of the atoms are freely shared by all the ions in the crystal, the metallic bonding is also referred to as electronic bonding.

Kossel

The ions have noble gas electronic configuration was suggested by Kossel.

(c) Nitrogen – Bond order 2. 

Actually N = N bond order is 3.

Ne, Ar

Na⁺ : 1s² 2s² 2p⁶ = [Ne]

Cl^- : 1s² 2s² 3s² 3p⁶ = [Ar]

Valence bond theory :

1. A covalent bond between two atoms is formed when the two atoms approach each other closely and one atom overlaps its valence orbital containing unpaired electron with the valence orbital of other atom that contains the unpaired electron of opposite spin. 

2. The greater the overlapping of the orbitals, the stronger will be bond. 

3. Valence bond theory gives a directional character to the bond when other than ‘s’ orbitals are involved. 

4. Electron pair in the overlapping orbitals is shared bv both the atoms involved in the overlapping. 

5. If orbitals overlap along internucleus axis, they form a strong bond called sigma (σ) bond. 

6. If the orbitals overlap laterally, they form a weak bond called pi (π) bond.

i) This statement is wrong. In polar compounds the more electronegative atom attracts the electron pair towards it which is known as electronegativity.

ii) Chlorine is more electronegative than Hydrogen. So the electron pair shifts more towards chlorine atom. Thus partial positive charge is formed on Hydrogen and partial negative charge is formed on Chlorine. So it is dipolar molecule. So the statement is true.

iii) This statement is false. The forces are not electrostatic and also they are weak.

iv) This statement is false because they can acquire by not only electron transfer but also mutually sharing of electrons.

v) This statement is false because ionic compounds are generally hard solids.

Correct option is  C) octet

Correct option is  A

(d) BF₃ – sp³d² 

Actually BF⁴ is sp² hybridised.

1. No, the electrostatic forces are non-directional. 

2. Therefore, it is not possible for one Na⁺ to be attracted by one Cl^- and vice-versa. 

3. Depending upon the size and charge of particular ion, number of oppositely charged ions get attracted by it, but, in a definite number.

4. In sodium chloride crystal each Na⁺ is surrounded by 6 Cl^- and each Cl^- by six Na⁺ ions. 

Ionic compounds in the crystalline state consists of orderly arranged cations and anions held together by electrostatic forces of attractions in three dimensions.

The crystals of electrovalent compounds are made up of crystal lattice containing oppositely charged ions. Each cation is surrounded by a definite number of anions and vice-versa. Their is a great electrostatic force of attraction among these oppositely charged ions and as a result, ionic compounds form hard crystals.

1) Given that B is inert gas. So the valency of A is 1 and it is a nonmetal and valency of C is 1 and it is metal and valency of D is 4 and it is a non-metal.

2) The bond formed between C and A is ionic nature and its formula is CA. The bond formed between D and A is covalent nature and its formula is DA₄.

Ionic compounds are polar in nature. So they are soluble in polar solvent like water whereas covalent compounds are non-polar in nature. So they are insoluble in water.

Steps to write Lewis dot structures :

• Add the total number of valence electrons of combining atoms in the molecule.
• In anions, add one electron for each negative charge.
• In cations, subtract one electron from valence electrons for each positive charge.
• Write skeletal structure of the molecule to show the atoms and number of valence electrons forming the single bond between the atoms.
• Add remaining electron pairs to complete the octet of each atom.
• If octet is not complete form multiple bonds between the atoms such that octet of each atom is complete.
• In polyatomic atoms and ions, the least electronegative atom is the central atom. 
• e.g. In \(SO_4^{2-}\) ion, ‘S’ is the central atom and in \(NO^-_3\), ‘N’ is the central atom.
• After writing the number of electrons as shared pairs forming single bonds, the remaining electron pairs are used either for multiple bonds or they remain as lone pairs.

Ionic compound

According to Fajan’s rule, with increasing size of the anion and with decreasing size of the cation, ionic character of the compound decreases while the covalent character increases.

Here, since the cation is same in both the compounds, the size of the anion decides the nature of the compound. Size of chlorine being greater than fluorine, AlCl₃ is covalent while AlF₃ is ionic.

1. Electronic confiuration of Be(Z = 4) is 1s² 2s² and electronic configuration of Cl (Z = 17) is 1s² 2s² 2p⁶ 3s² 3p⁵ .

2. Beryllium has 2 electrons in its valence shell and chlorine atoms (2) have 7 electrons in their valence shell.

3. By losing two electrons, Beryllium attains the inert gas configuration of Helium and becomes a dipositive cation, Be²⁺ and each chlorine atom accepts one electron to become (Cl^-) uninegative anion and attains the stable electronic configuration of Argon.

4. Then Be²⁺ combine with 2Cl ions to form an ionic crystal in which they are held together by electrostatic attractive forces.

5. During the formation of 1 mole of BeCl₂ , the amount of energy released is – 468 kJ/mol. This favours the formation of BeCl, and its stabilisation.

MgCI₂ bond formation:

1. Electronic configuration of Mg (z = 12) is 1s² 2s² 2p⁶ 3s² .

Electronic configuration of Cl (z = 17) is 1s² 2p⁶ 3p⁶ 3p⁵

2. Magnesium has 2 electrons in its valence shell and chlorine has 7 electrons in its valence shell.

3. By losing two electrons, magnesium attains the inert gas configuration of Neon and becomes a dipositive cation (Mg²⁺) and two chlorine atoms accept these electrons to become two uninegative anions [2Cl^-] by attaining the stable inert gas configuration of Argon.

4. These ions, Mg²⁺ and 2Cl^- combine to form an ionic crystal in which they are held together by electrostatic attractive forces.

5. The energy released during the formation of 1 mole of MgCl₂ is –783 kJ/mole. This favours the formation of MgCI₂ and its stabilisation.

MgCl₂ has sp hybridisation, whereas SnCl₂ has sp² hybridisation. Sign shown in representing the orbitals.

Yes. I think that pairs of Na⁺ Cl^- as units would be present in the solid crystal.

C) a → iv, b → i, e → ii, d →iii

Due to the repulsion between the lone pair of electrons and bond pair of electrons in water molecule the bond angle will be 104° 31′ rather than 109° 28′.

Due to strong attractive forces they are usually hard crystals.

Correct option is  B) 6

(B) Ammonium chloride has all the three electronic bonds.

NaCl < MgCl₂ < AlCl₃.

i. No, 

The representation is incorrect. 

There will be no lone pair of electrons on aluminium.

ii. The number of electrons present in the valence shell of aluminium will be six.

Ionic compounds exist in crystalline state.

D) All of these

Correct option is  c) 1:6

Sodium chloride has face centered cubic structure. Calcium chloride has body centered cubic structure.

(D) Ammonium chloride

A) a → ii, b →i, c → iii

i. H-I : Polar 

ii. H-O-H : Polar 

iii. H-Br : Polar 

iv. Br₂ : Nonpolar 

v. N₂ : Nonpolar 

vi. I₂ : Nonpolar 

vii. NH₃ : Polar

Electrostatic forces of attraction are present in ionic bonds.

No. Elements and compounds are not simply made up of separate atoms individually arranged.

a) The element with atomic number 15 is phosphorus. Its electronic configuration is 2, 8, 5. So its valency is 3 and it is a solid non-metal.

b) The element with atomic number 8 is oxygen. Its electronic configuration is 2, 6. So its valency is 2 and it is a gas.

c) The element with atomic number 19 is potassium. Its electronic configuration is 2, 8, 8, 1. So its valency is 1 and it is a metal.

d) The element with atomic number 14 is silicon. Its electronic configuration is 2, 8, 4. Its valency is 4 and it is a nonmetal.

NaCl dissolves in water because of hydration. Water being a polar molecule has positive and negative ends which hydrate Na⁺ and Cl^- ions. Benzene being non-polar cannot solvate the ions of NaCl.

1. Two electrons are transferred from Magnesium atom to Chlorine atom in the formation of Magnesium chloride. 

2. So Magnesium is oxidised (loss of electrons is oxidation) and Chlorine is reduced (gain of electrons is reduction).

1) Number of electrons in their outermost shell. 

2) Bond strength between the atoms in compound.

1) Atoms which have 8e“ in their outer shell will not combine. 

2) Atoms which have more than or less than 8e“ in their outer shell will combine.

i) NaBr, CaO have only ionic bond in the molecules,

ii) N₂ has a triple covalent bond in its molecule (N ≡ N )

iii) Generally ionic compounds are solids. So NaBr, CaO are solids. I₂ being a covalent compound still it is solid.

iv) O₂ has a double covalent bond in its molecule (O = O).

v) The non-polar covalent liquid is Br₂.

Bond angle in H₂O molecule is 104° 30′. Bond angle in NH₃ molecule is 107°.

Option : C is correct.

Valencies of the atoms participating in the molecules.

Sp-hybrid orbital has greater directional character than p-orbital. Because in case of p-orbitals, the two lobes are equal in size and equal electron density is distributed whereas in Sp-hybrid orbital, electron density is greater on one side.

(ii) H₂O > HF > NH₃

i. σ bond 

ii. π bond 

iii. σ bond 

iv. σ bond

i. Sigma overlap (σ bond) : 

When two half-filled orbitals of two atoms overlap along the internuclear axis, it is called as sigma overlap or sigma bond.

ii. pi overlap (π bond) : 

When two half-filled orbitals of two atoms overlap side-ways (laterally), it is called as π overlap or π bond.