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Robert Estrada
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Joined: Fri Sep 29, 2017 7:05 am


Postby Robert Estrada » Wed Nov 08, 2017 8:50 pm

How do you tell if a species is a radical such as in question 55... is it a, b, c or d?
a. NO2-
b. CH3
c. OH
d.. CH2O

Abigail Yap 2K
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am

Re: 3.55

Postby Abigail Yap 2K » Wed Nov 08, 2017 8:57 pm


Radicals have unpaired electrons. To determine which of these species are radicals, we simply calculate the number of valence electrons that each has; those with an odd number of electrons will have an unpaired electron and therefore be a radical species. Answer choices b and c are radicals.

Clarisse Wikstrom 1H
Posts: 63
Joined: Fri Sep 29, 2017 7:05 am

Re: 3.55

Postby Clarisse Wikstrom 1H » Wed Nov 08, 2017 8:59 pm

It may also help to draw out the lewis structures for each one. If an atom in one has an unpaired e-, then the species is a radical.

Mike Vinci 2B
Posts: 49
Joined: Fri Sep 29, 2017 7:03 am
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Re: 3.55

Postby Mike Vinci 2B » Wed Nov 08, 2017 9:05 pm

Hey Robert, so in chemistry, species are know to be atoms, molecules, ions, and so on. For this specific problem asking about radicals, radicals are species that have an unpaired electron. As a result of this condition, they have an odd number of valence electrons and do not fill their outer valence shell. Using this information, we can choose (b) and (c) to be the correct answer because if you draw the Lewis dot structure, you'll see that they have an unpaired electron. For (a) and (d), all their electrons are paired, and this can also be seen with a Lewis dot structure. Building on the concept of radicals, many can be highly reactive due to the unpaired electron, such as CH3.

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