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chemistry MCQ

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ashwinkandel:
i have attached question of chemistry. i am confused with question number 2. how do we determine the proton, neutron and electrons of the compounds given in option B, C and D respectively.

ashwinkandel:
one more question . i m having problem with question no. 5 in the following attachment. can someone reply me with the solution and reasoning. i am having my chemistry internal exams tomorrow so plz reply me quickly.

nid404:

--- Quote from: ashwinkandel on October 04, 2010, 01:35:39 pm ---i have attached question of chemistry. i am confused with question number 2. how do we determine the proton, neutron and electrons of the compounds given in option B, C and D respectively.

--- End quote ---

B- H3O+

here's the structure.



There are 8 electrons + 2 in the first orbit of O.  = 10 electrons. Neutrons= 8(no neutrons in H) in O Protons=8  and 1 each H= 11

C- OD-

So O2- and D+ --> OD-

10 electrons, 9 neutrons(Deuterium has 1 neutron) and 9 protons(8 of O and 1 of D)

D- OH-


So O2- + H+--> OH-

10 electrons, 8 neutrons(no neutrons in H) and 9 protons( 8 in O and 1 in H)

Questions asks which one has more electrons than protons. So B is ruled out.

Now which one of C and D have more protons than neutrons. It's D. Hence D :P

nid404:

--- Quote from: ashwinkandel on October 04, 2010, 02:36:41 pm ---one more question . i m having problem with question no. 5 in the following attachment. can someone reply me with the solution and reasoning. i am having my chemistry internal exams tomorrow so plz reply me quickly.

--- End quote ---

8 electrons.

Electronics config.

1s22s22p4

A is not the right configuration because electrons do not couple when there's an empty pz orbital.
B is the right one, the electrons fill up individually first in px, py and pz and then start coupling after each of them has at least 1 electron.
C and D are hybridized states..high energy.

So B

nid404:

--- Quote from: Theonlyone on October 04, 2010, 03:19:08 pm ---Was going to post...
anyways, got your 1st answer!!

Ms. Garfieldo. :P

The orbit nearest to the nucleus has the most energy!

So the electrons will start filling in different orbitals.

See the 2px orbital, the left of the three orbitals, it has got only one electron, and hence, others have two in them.

so this atom will be in it's lowest energy state compared to the others.
I tried, hope i was not wrong and u understood!!  8)

--- End quote ---

What according to you is the answer to this question?  ::)

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