1 g-chem question

[Keroro]

Choose the CORRECT physical properties pertaining to ionic compounds.

I. Strong conductors of electricity in solid states
II. High melting points
III. Hard and brittle
IV. Ductile and malleable

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[wlee009]

I. Strong conductors of electricity in solid states ---> Incorrect. Ionic compounds conduct electricity only in liquid or gas state
II. High melting points ---> Correct
III. Hard and brittle --->Correct
IV. Ductile and malleable --->Incorrect. It's the characteristic of metallic bonds i think

 

[RockstarDMD]

ionic solids conduct electricity in the solid or molten state.

 

[usc1122]

so, are they strong conductors of electricity in solid or gas and liquid state??

 

[54807]

ionic solids conduct electricity in the solid or molten state.

I always thought ionic solids conduct electricity poorly. Metals conduct electricity because they don't hold onto their electrons very easily, right? Well I always thought ionic compounds behave differently. For example, water is H2O and it exists as a bunch of H2O molecules all interacting. Well the ionic compounds don't stay as molecules. If XY is the ionic compound by itself when you get them all together in a big pile, the X isn't attached the Y like the hydrogens are connected to the oxygen. It's kinda like the electrons/bonding is spread amongst all the atoms so it's really hard to rip the electrons out.

This is how it was presented in a material engineering course. So...it might be presented in a dumbed down way because it wasn't a theory chem course...

Does that spark anyone's memory or anyone have a correction?

 

[djeffreyt]

I agree with Wlee and Saxy, ionic solts do not conduct electricity well. Only choices II and III are correct. You cannot use a hardened mass of table salt to conduct an electrical current.

 

[Immuno-guy]

I agree with Saxy et al. Ionic solids don't share electrons with each other let alone with other molecules. Metals have a 'sea of electrons', this is the opposite.

I think the correct answer is brittle and high melting point.

When you knock an ionic solid the +ve and -ve charges are now alligned with each other (think + and +) so instead of attracting each other they repel therefore the solid easily cleaves.

The highly ordered structure of an ionic crystal solid (think table salt) has a great deal of order to loose before it will melt into a less ordered state.

 

[SgtSadhu]

yea I agree with the answers yall have put down.

The ionic molecules cant conduct electricty well in solid state but can do so in the liquid/aqueous state

And metallic bonds are no ionic but rather covalent bonds and thus are able to be good conducters as solids