In this video excerpt from NOVA"s "Hunting the Elements," New York Times innovation columnist David Pogue examines how atomic structure determines retask. Meet Theo Gray, chemist and also author, that helps David discover how the electron configuration of an atom affects its capability to combine through various other atoms. Find Out why noble gases are not reenergetic and also why halogens and also alkali metals are extremely reactive.

You are watching: What does the reactivity of an atom depend on

Permitted use:



Source: NOVA: "Hunting the Elements"

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

Here are some of the main ideas students should take ameans from this video:

The area of electrons in an atom can be explained as concentric shells approximately the nucleus of the atom.The variety of electrons in the outermany shell of an atom determines its reactivity. Noble gases have low reactivity bereason they have complete electron shells.Halogens are extremely reenergetic bereason they easily gain an electron to fill their outerthe majority of shell.Alkali metals are very reenergetic bereason they easily shed the single electron in their outerthe majority of shell.

Questions for Discussion

Why are noble gases occasionally referred to as inert gases?Think of and also describe an analogy to assist you remember whether noble gases are reactive.What does the organize intend when he states “retask is a shell game”?In terms of electrons, what do elements located in the very same column of the periodic table have actually in common?


DAVID POGUE (Technology Guru): The noble gases.

See more: Black Light Vs Glow In The Dark, Glow In The Dark Vs Fluorescent Paint

Wright here does that term "noble gases" come from? Are they nobility? Do they rush to rescue maidens?

THEO GRAY (Chemist and Author): No, you"re thinking of heroes. They are prefer the aristocracy in the sense that they do not mix through the riffraff. They don"t favor to react with any type of other aspects.

By and also big, it"s not possible to create compounds with them.

DAVID POGUE: Well, it"s a shame for your repertoire that they are gases, because you"ve acquired substantial blanks here. Oh, ho, ho, ho! The noble gases, choose neon and also argon, pose a trouble for chemists that favor their aspects to join pressures and also react with each various other. You have the right to run an electrical current via them, excite their electrons and also obtain pretty colors—which is just how neon lights work—however the noble gases do not react.

They pretty a lot refusage to incorporate with various other facets.

THEO GRAY: Being an inert gas, being unwilling to mix with the various other aspects, react via them, this is a really clear-cut difference that sets apart this particular column from all the others in the routine table.

DAVID POGUE: So why are these men so aloof? As it turns out, protons may recognize the identity of an facet, but electrons preeminence its reactivity. And reactivity is a shell game.

Here"s exactly how the game is played.

Imagine that these balls are electrons, and the tarobtain is an atom. Electrons don"t simply pile on around the nucleus. As with skee-sphere, wright here you land also, relative to the center counts.

Oh come on!

The electrons take up positions in what deserve to be believed of as concentric shells. The first shell maxes out at just 2 electrons, the next holds eight, then it goes approximately eighteenager. An atom via eight electrons in its outer shell renders one happy, satisfied atom.

And noble gases come pre-equipped through entirely satisfied shells.

And is this the only column favor that?

THEO GRAY: It"s the only column where all the shells are completely filled.

DAVID POGUE: But what around the column simply prior to those secure noble gases? They are called the halogens. They have actually an outer shell that demands just another electron to be full. And they"ll grab it any way they have the right to. The group consists of fluorine and bromine, but the most infamous is chlorine: 17 prolots surrounded by 17 electrons, arranged in three shells of 2, eight and also seven, one brief of being complete.

It"s that additional electron chlorine will certainly obtain any kind of way it can, sometimes with violent outcomes. That"s why chlorine gas was offered as a deadly poiboy in World War One.

THEO GRAY: Chlorine, I expect, this is nasty stuff. This will certainly take electrons from kit10s. It"ll go and also steal an electron from off the water in your lungs and rotate it to hydrochloric acid, because it really wants an electron.

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

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

DAVID POGUE: The alkali steels are the initially column. Each of them has actually complete shells, plus one added electron sitting in a brand-new, outer shell.

They have actually acquainted names favor lithium, sodium and also potassium. And they all want to eliminate that single, lonely electron, any type of way they have the right to.