[Plumbum]

Hi guys,

i need your help with a quiz. I dont have the solution and I was wndering if you coudl help me out with the solution???

THANK U

Point defects that form in a crystal exposed to radioactivity are called:
(a) Intrinsic defects
(b) Induced defects
(c) Native defects

My answer is b

Intrinsic defects in crystals:
(a) Are always present
(b) Only form if two or more different atom species occur
(c) Only form in the presence of impurities

My answer is a

Impurity atoms are:
(a) Intrinsic defects
(b) Extrinsic defects
(c) Native defects

My answer is b

An impurity P atom on a Si site in a crystal of silicon is a:
(a) Interstitial defect
(b) Antisite defect
(c) Substitutional defect

My answer is b

The number of Schottky defects in a crystal of formula MX is equal to:
(a) Half the total number of vacancies present
(b) The total number of vacancies present
(c) Double the total number of vacancies present

I have actually no idea .

A single anion Frenkel defect in an ionic crystal of formula MX2 needs to be
balanced by:
(a) A cation Frenkel defect
(b) Two cation Frenkel defects
(c) Nothing

I dnt know...

7. A metal atom N on an M site in a crystal MX would be written:
(a) N_M
(b) M_N
(c) N_MX

My answer is b

An anion vacancy in an ionic oxide has the symbol:
(a) V^x_O
(b) V^2'_O
(c) V^2°_O

My answer is c

A Ca²⁺ ion on a Na⁺ site in a crystal is written:
(a) Ca^x_Ca
(b) Ca^°_Na
(c) Ca^'_Na

i...dont know

Last question in picutre ... my answer is a :S

thank u thank u so much

[Enthalpy]

For P replacing Si, I'd say it's substitutional. It needs a crystal composed of different atoms like GaAs to observe an antisite defect.

I agree with your three first answers and ignore the rest - sorry.

[Plumbum]

Okay thank you. I think I got the answers now, I did some further research. But I still have one huge problem..:S

Can you or somebody please help me with understanding defect equations??

For example if there is a question like: Write defect equations for the following reactions:
(a) MgO doped with Li2O

what the hell...I already tried it myself and I als did some research but I am abslolutley clueless. Can someone pls pls help:(?