Cheemistry!!!!!!!!?

Question

How can I identify a di-pole di-pole force?
How can I identify a polar or non-polar or covalent bond?
What does the "smallest or largest radius" mean? (not in a circle for math)

Answer 1

Dipole-dipole forces occur between two polar molecules. A polar molecule has partially positive and partially negative charges at opposite ends of the molecule due to differences in electronegative values of the atoms involved in the bonds. HF is a polar covalent bond because H = 2.1 and F = 4.0. The difference between them is 4.0 - 2.1 = 1.9 (polar) The H end has the lower electronegative value and carries a partially positive charge. The F end has the higher electronegative value and carries a partially negative charge. The fact that this molecule has different partial charges at each end makes it a dipole.

Polar and nonpolar covalent bonds are determined by comparing the electronegative values for the two atoms involved in the bond. A general guideline (differs from one text to another) 0-0.3 = nonpolar covalent bond; 0.4-1.9 = polar colvalent bond; 2.0 and above = ionic bond.

A metallic atom will lose electrons to form a metallic ion (cation). This means the atomic radius is the largest in metallic atoms at the bottom of the group (family). A nonmetallic atom will gain electrons to form a nonmetallic ion (anion). This means the largest ionic radius is found in nonmetallic ions at the bottom of their groups.

Answer 2

Question 2 first:
Polar (polar covalent) bond involves two atoms with electronegativities that differ by 0.4 - 1.7 units (below this range, the bond is non-polar covalent, above this range the bond is ionic).
A covalent bond involves two non-metallic atoms or hydrogen, for example C-H, N-O, H-O, Cl-H, C-Cl, all of these are good examples of polar covalent except C-H. Non-polar covalent examples: C-C, H-H, N-Cl.

Question 1: Dipole-dipole forces exists between molecules containing polar covalent bonds. So two molecules of H-Cl will exert dipole-dipole force on each other.

Question 3: This can only be taken in a mathematic sense, but it applies to a sphere rather than a circle. I'm guessing they're talking about the relative sizes of ions or atoms. The rules of comparison are as you go down the periodic table, the radius increases considerably. As you go right to left across the periodic table, the size (radius) also increases. So for example, K is larger than Ca which is larger than Mg.

Answer 3

This is quiet important in chemistry..........

so build ure concept.........

i will start from the basics..........

dipole-dipole interaction(or forces) are the forces of attraction occuring among the polar molecules...........

The reason for the origin of these forces is ver easy man..........Polar molecules have permanent dipoles.The positive pole of one molecule is attracted by the negative pole of the other molecule.....

EXAMPLE....
A simple example of HCl in which chlorine being more electronegative acquires a negative charge where as hydrogen becomes positivly charged.....So this way dipole - dipole attractions are present in HCl molecule...







Second question.......

Polar (polar covalent) bond involves two atoms with electronegativities that differ by 0.4 - 1.7 units

A covalent bond involves two non-metallic atoms or hydrogen,

for example
C-H
N-O
H-O
Cl-H
C-Cl

all of these are good examples of polar covalent except C-H.

Non-polar covalent examples:
C-C
H-H
N-Cl









Third question...........

u can understand with the help of cation and anion.......

A metallic atom will lose electrons to form a metallic ion (cation).
This means the atomic radius is the largest in metallic atoms at the bottom of the group .

A nonmetallic atom will gain electrons to form a nonmetallic ion (anion). This means the largest ionic radius is found in nonmetallic ions at the bottom of their groups.

also learn one thing...

as we move from top to bottom in the periodic table...

electronic shells are added each time

size INCREASES

And as we move from left to right in the periodic table the size becomes smaller and smaller..............

hope it works...

all the best.........

Answer 4

by looking at electronegativty, if there is a large difference in a bond in an unsymmetrical molecule then it will be. Oxygen, halogens and nitrogen are rather electronegative