Inter and Intra molecular bonds (1 Viewer)

[housemouse]

Ive been having trouble with bonds in Chemistry since last year:
Could someone outline all the bonds and how i would identify each one
thank you

 

[m0ofin]

Yay! We learnt that recently I'll give my 2 cents but I'm not sure if it's what you're looking for or if I'm entirely correct.

IONIC
- formed between a non-metal and a metal
- Involves the giving and taking of electrons
- formed between positive (cations) & negative (anions) ions
- no molecules
- formula is a ratio only (empirical?)
- doesn't conduct electricity when solid but does when molten or in solutions
- bonds are weaker than covalent but still strong
- intermediate melting and boiling points (eg: NaCl t_m and t_b is 1122ºc and 1465ºc

COVALENT MOLECULAR
- Involves the sharing of electrons, they want a full outer shell - octet rule
- between 2 non-metals
- Covalent molecular compounds contain small molecules with very strong bonds within the molecule (Intra) and very weak bonds (Inter) between molecules

For example: Water is a molecular covalent bond. The Hydrogens are stuck very strongly to the Oxygens with Intra-molecular bonds and it's hard to separate them (unless you heat them very highly), and molecules of water can stick to each other with Inter-molecular bonds. That's why they are easily melted when frozen.

- Inter-molecular bonds are also called dispersion forces I think.
- Low t_m and t_b (eg: Ethanol t_m and t_b is -114.1ºc and 78.3ºc)
- If Intermolecular forces didn't exist in substances then they'd only exist as gases.

COVALENT NETWORK
- no separate molecules, one large one eg: diamond
- very strong bonds - these substances are very hard
- very high t_m and t_b (eg: TiC 3140ºc and 4820ºc)

 

[pLuvia]

The different kind of intermolecular bonds are dipole-dipole, dispersion and hydrogen bonds. Where hydrogen is the strongest out of all of them, which occur with hydrogen, fluoride, oxygen and nitrogen

 

[+:: $i[Q]u3 ::+]

The summary above is good.

The different kind of covalent bonds are dipole-dipole, dispersion and hydrogen bonds. Where hydrogen is the strongest out of all of them, which occur with hydrogen, fluoride, oxygen and nitrogen

Dipole-dipole, dispersion forces and hydrogen bonds are not types of covalent bonds. Covalent bonding is a specific form of intramolecular bonding where atoms within the molecule share electrons.

The three types of bonding mentioned here are the three different types of intermolecular forces that occur between molecules in covalent molecular substances. Think of it as a guide to the melting point/ boiling point of the covalent molecular substance, since MP/BP depends on the strength of the forces between the molecules. If it has a very low melting poing (eg O2, CO2, methane), chances are that only dispersion forces are present. Whereas H2O has a very high melting point for such a small molecule due to H bonds.

 

[Dreamerish*~]

The different kind of covalent bonds are dipole-dipole, dispersion and hydrogen bonds. Where hydrogen is the strongest out of all of them, which occur with hydrogen, fluoride, oxygen and nitrogen

Covalent bonds are intramolecular bonds, while dipole-dipole, dispersion and hydrogen bonds are intermolecular bonds.

The Hydrogens are stuck very strongly to the Oxygens with Intra-molecular bonds and it's hard to separate them (unless you heat them very highly)

You separate the hydrogen atoms and oxygen atoms in water by electrolysis.

Inter-molecular bonds are also called dispersion forces I think.

Dispersion forces is just one type of intermolecular bonds. Others are dipole-dipole and hydrogen bonds.

I'll just add that covalent network substances have a continuous lattice structure. For example, in diamond, each carbon atom is connected to four other carbon atoms forming a rigid 3D structure, like so:

... while in graphite, the carbon atoms are joined to form a 2D structure, like so:

This forms layers, which unlike diamond, can slide over each other. This is why graphite is so much softer.

 

[Riviet]

Just to clarify things, intramolecular bonds are the bonds that exist within a molecule and intermolecular bonds are the bonds that exist between molceules.