Question

20)Categorize (give examples) the direct and indirect electronic effects.

1) Why do atoms bond?

2) What is electronegativity?

3) What do you mean by dipole moment? Explain, considering water molecule as an example.

4) Why chloroform (CHCl3) is polar whereas carbon tetrachloride (CCl4) is non-polar?

5) NH3 is a polar molecule but BF3 is non-polar—justify.

Answer 1

20) the electric effect has to do with the interaction of electrons of different atoms in a molecule, or the presence of certain groups in certain chemical environment. The electronic effect of atoms has to do with its electronegativity. A natural atomic property. Some molecular groups are able to transfer or to abstract electronic density, and this is what is known as electronic effect.

Direct electronic effects are those that occur intramolecular level.

For example: Halogens linked to aliphatic or aromatic organic molecules abstract electron density for its electronegative nature.
Methyl groups give electron density to be part of a molecule, for example, the methyl group of toluene, give electron density to the aromatic ring.

Indirect Electronic Effects are those that occur intermolecular level

For example: The hydrogen bonds in water molecules, electronic effects are indirect, since the charge difference of oxygen and hydrogen atoms generate the interaction of the positive and negative poles between molecules. This occurs because the electronegativity of the oxygen atom (partially negative), making it capable of interacting with the partially positive hydrogens.

1) Atoms form bonds because they are able to share electrons to form a more stable species. When speaking bond, speaking of shared electrons.

2)  Is a natural property of each atom beams capable of abstracting or concentrate electronic density. for this reason electronegative atoms are partially negative, and labile to electrophilic attack.

3) It represents the distribution of charges in a molecule. It occurs whenever there is a separation of positive and negative charges, and charge will be concentrate in greater electronegativity atom.

Water molecula is formed for oxygen and hydrogen atoms. Oxygen is electronegatic atom and represents negative pole, and hydrogen atoms are positive pole. Negative charge is concentrate to the oxygen atom.

4) Because Chloroform presents a heterogeneous distribution of the charge, Cl atoms are partially negative and H are partially positive. For CCl4 distribution of the charge is homogeneous forthere is non polar.

5) NH3 have electron pair nonbonding, representing negative pole abstracting the charge of the hydrogen atoms, these resultpartially positive . For this asymmetry Charge the NH3 molecule is polar.

BF3 do not have electron pair nonbonding, forthere charge distribution is simetric or homogeneus. fluor atoms abstracts electronic density for equal.