In this video excerpt native NOVA"s "Hunting the Elements," New York Times technology columnist David Pogue examines how atomic structure determines reactivity. Fulfill Theo Gray, chemist and also author, who helps David explore how the electron configuration of an atom affect its capability to combine with various other atoms. Uncover why noble gases room not reactive and also why halogens and alkali metals are highly reactive.

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Source: NOVA: "Hunting the Elements"

This media asset was excerpted native NOVA: "Hunting the Elements."

Here are several of the main ideas students have to take away from this video:

The place of electrons in an atom can be defined as concentric shells approximately the nucleus of the atom.The variety of electrons in the outermost covering of one atom identify its reactivity. Noble gases have actually low reactivity because they have full electron shells.Halogens are extremely reactive due to the fact that they readily get an electron to to fill their outermost shell.Alkali metals are highly reactive because they readily lose the solitary electron in their outermost shell.

Questions because that Discussion

Why are noble gases sometimes called inert gases?Think of and describe one analogy to assist you remember whether noble gases space reactive.What walk the host mean when he says “reactivity is a covering game”?In terms of electrons, what do facets located in the same shaft of the regular table have in common?


DAVID POGUE (Technology Guru): The noble gases.

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Where does the term "noble gases" come from? room they nobility? execute they sirloin to rescue maidens?

THEO GRAY (Chemist and Author): No, you"re thinking of heroes. They room like the aristocracy in the sense that they don"t mix with the riffraff. Castle don"t choose to reaction with any type of other elements.

By and large, it"s not possible to form compounds through them.

DAVID POGUE: Well, it"s a shame because that your repertoire that they are gases, since you"ve got large blanks here. Oh, ho, ho, ho! The noble gases, like neon and also argon, attitude a difficulty for chemists who favor their elements to join forces and react through each other. You have the right to run an electric present through them, excite your electrons and get nice colors—which is exactly how neon lamp work—but the noble gases don"t react.

They pretty much refuse to combine with other elements.

THEO GRAY: gift an inert gas, being unwilling to mix v the other elements, react v them, this is a really clear-cut difference that to adjust apart this particular column from all the others in the routine table.

DAVID POGUE: so why space these men so aloof? together it turns out, protons may determine the identification of one element, however electrons dominion its reactivity. And reactivity is a covering game.

Here"s exactly how the video game is played.

Imagine the these balls space electrons, and the target is one atom. Electrons don"t simply pile on around the nucleus. Similar to skee-ball, wherein you land, family member to the facility counts.

Oh come on!

The electrons take it up location in what have the right to be thought of as concentric shells. The first shell maxes out at just two electrons, the following holds eight, climate it goes approximately eighteen. One atom v eight electron in its outer shell provides one happy, to solve atom.

And noble gases come pre-equipped with totally satisfied shells.

And is this the only obelisk like that?

THEO GRAY: It"s the only pillar where every the shells are completely filled.

DAVID POGUE: however what about the tower just before those secure noble gases? lock are dubbed the halogens. They have actually an outer shell that needs just one much more electron to it is in full. And they"ll grab that any way they can. The group includes fluorine and bromine, but the most infamous is chlorine: 17 protons surrounding by 17 electrons, arranged in three shells that two, eight and seven, one quick of being full.

It"s that extra electron chlorine will obtain any means it can, periodically with violent results. That"s why chlorine gas was provided as a deadly poison in people War One.

THEO GRAY: Chlorine, i mean, this is nasty stuff. This will certainly take electrons from kittens. It"ll go and steal one electron from turn off the water in her lungs and also turn it come hydrochloric acid, due to the fact that it really desires an electron.

DAVID POGUE: Yeah, possibly I"ll leave that whereby it was.

THEO GRAY: Now, if you go the various other direction, you finish up with the alkali metals.

DAVID POGUE: The alkali steels are the first column. Every of lock has complete shells, to add one extra electron sitting in a new, external shell.

They have acquainted names like lithium, sodium and potassium. And they all want to get rid of that single, lonely electron, any means they can.