Answer the questions in the table below about the shape of...

Answer the questions in the table below about the shape of the phosphorus trifluoride (PF3) molecule. How many electron groups are around the central phosphorus atom? Note: one "electron group" means one lone pair, one single bond, one double bond, or one triple bond. What phrase best describes the arrangement of these electron groups around the central phosphorus atom? (You may need to use the scrollbar to see all the choices.) (choose one)

Transcript

00:03 Hi there.

00:03 In this question, we are working with the p f3 molecule.

00:08 And the first thing we want to do is to draw the lewis structure for this so that we can see the arrangement of the atoms and if there are any lone pairs.

00:19 So to draw the lewis dot structure, we need to know how many valence electrons.

00:24 Well, phosphorus is in group five of the periodic table.

00:27 So all of the elements in group 5a have five valence electrons.

00:31 Flooring is a halogen.

00:33 And, and halogens are in group 7a, so all halogens have seven valence electrons.

00:38 This gives us a total of 26 valence electrons.

00:46 And in lewis dot structures, we represent valence electrons as dots.

00:51 So our dot structure needs to have 26 dots in it.

00:55 We always put the single element in the center and surrounded by the element that we have more than one of.

01:04 So this would be our skeleton structure for pf3.

01:08 We know that each flooring needs to be held to the phosphorus with at least a single bond.

01:14 So we'll start off with single bonds there.

01:16 That uses six of our 26 electrons.

01:19 Now we're going to start completing octets.

01:22 So there's one, two, three, four, five, six.

01:24 So there's eight dots around that fluorine, eight around this fluorine, eight around this fluorine.

01:33 That uses 24 of our total dots, which means we have two more remaining.

01:39 Well, phosphorus does not have an octet yet.

01:42 So those two dots are going to go on the phosphorus as a lone pair.

01:47 Okay, so now we're ready to answer our questions.

01:49 The first one wants to know how many electron groups around the central phosphorus...

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