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assignments unit 3 component 3

Hydrogen and also alkali metals

Alkali earth metals

Nobel gases

Hydrogen and also Alkali Metals

Characteristics of team 1 the the periodic table.

You are watching: Most reactive metal on periodic table

· recognize theelementsin team 1 of the periodic table.

· define why group 1elementsare very reactive.

· List various other properties of alkalimetals.

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You probably think ofwateras a problem that have the right to put the end fires. But someelementsare therefore reactive that they burn in water. In fact, they essentially explode in water. That’s what is continue in the picture above. Around 3 pounds of sodium were added to water, and the an outcome was this explosive reaction. Why is sodium such a reactive element? In this lesson friend will uncover out.

The very first Group

Sodium (Na) is an element in group 1 of the routine table of the elements. This team (column) that the table is shown below. It contains the nonmetal hydrogen (H) and sixmetalsthat are calledalkali metals. Aspects in the same team of the regular table have the same variety of valenceelectrons. These space the electrons in their outerenergy levelthat have the right to be connected in chemistry reactions. Valence electrons determine plenty of of the properties of an element, so facets in the same team have comparable properties. Every the facets in group 1 have just one valence electron. This renders them very reactive.

Q:Why does having actually just one valence electron make group 1 elements really reactive?

A:With simply one valence electron, team 1 facets are “eager” to shed that electron. Law so allows them to attain a complete outerenergy leveland maximum stability.

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Reactivity of team 1 Elements

Hydrogen is a really reactive gas, and the alkalimetalsare even an ext reactive. In fact, they room the many reactive metals and, along with the facets in team 17, space the many reactive of all elements. The reactivity of alkali metals increases from the optimal to the bottom the the group, so lithium (Li) is the least reactive alkali metal and francium (Fr) is the most reactive. Because alkali steels are therefore reactive, they are discovered in nature just in combination with other elements. Castle often combine with group 17 elements, i beg your pardon are an extremely “eager” to get an electron. In ~ the URL below, you deserve to watch a video that reflects just exactly how reactive the alkali metals are.

http://youtu.be/uixxJtJPVXk(2:22)

Other nature of Alkali Metals

Besides being very reactive, alkali steels share a variety of other properties.

· Alkali metals are allsolidsat roomtemperature.

· Alkali steels are low in density, and also some of lock float onwater.

· Alkali steels are fairly soft. Some are even soft enough to cut with a knife, choose the sodium pictured in theFigurebelow.

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A Closer Look

Although all group 1 elements share specific properties, such as being very reactive, they are not alike in every way. Three different group 1 facets are defined in much more detail listed below (Figuresbelow,below, andbelow). Notification the means in i m sorry they different from one another.

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Hydrogen has the smallest, lightest atom of every elements. Pure hydrogen is a colorless, odorless, tasteless gas that is nontoxic but highly flammable. Hydrogen gas exists greatly as diatomic (“two-atom”) molecule (H2), as presented in the chart on the right. Hydrogen is the most abundant aspect in the universe and the 3rd most abundant aspect on Earth, emerging mainly in link such as water.


Q:Why perform you think hydrogen gas commonly exists as diatomic molecules?

A:Each hydrogen atom has actually just one electron. As soon as two hydrogenatomsbond together, they share a pair ofelectrons. The shared electrons to fill their onlyenergy level, providing them the many stable arrangement of electrons.

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Potassium is a soft, silvery steel that ignites explosively in water. It conveniently loses the one valence electron to form positive potassium ion (K+), i beg your pardon are needed by every living cells. Potassium is so vital for plants the it is found in practically all fertilizers, favor the one displayed here. Potassium is numerous in Earth’s late in minerals such as feldspar.


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Francium has one that the largest, heaviest atom of all elements. Its one valence electron is much removed indigenous the nucleus, together you deserve to see in the atomic version on the right, so it is easily removed from the atom. Francium is radioactive and quickly decays to kind other elements such as radium. This is why francium is incredibly rare in nature. Much less than an oz of francium is existing on earth at any given time.


Q:Francium decays too conveniently to formcompoundswith various other elements. Which elements to friend think it would bond v if it could?

A:With one valence electron, francium would bond v a halogen facet in group 17, which has actually seven valenceelectronsand needs one more to to fill its outer power level. Aspects in group 17 incorporate fluorine and also chlorine.

Summary

· team 1 the the regular table consists of hydrogen and the alkali metals.

· due to the fact that they have just one valence electron, team 1 facets are very reactive. Together a result, castle are uncovered in nature only in mix with other elements.

· Alkali metals are allsolidsat roomtemperature. Lock are fairly soft and low in density.

· from the height to the bottom of group 1, the aspects have heavier, an ext reactiveatoms.

Explore More

At the following URL, click on “Group 1 data and also graphs.” usage the data in the group 1 table to fill in the blanks below with eitherincreasesordecreases.

http://www.docbrown.info/page07/sblock.htm

From the optimal to the bottom of team 1, properties of the alkali metals change as follows:

1. Melting point __________.

2. Boiling point __________.

3. Density __________.

4. Atomic radius __________.

5. Variety of electrons __________.

Review

1. What are alkali metals?

2. Why is hydrogen, a nonmetal, inserted in the same group as the alkali metals?

3. Explain why team 1 elements often formcompoundswith facets in team 17.

4. Compare and contrast hydrogen and also francium.

Alkaline planet Metals

Characteristics of group 2 of the periodic table.

· recognize alkaline Earthmetals.

· perform properties that alkaline Earthmetals.

· describe why alkaline Earthmetalsare an extremely reactive.

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Sparklers like the one this girl is holding make festive additions to many celebrations. You may use castle yourself. Yet watch out if girlfriend do because their flames space really hot! The shining white flames are developed when magnesium burns. Magnesium is a light- weight steel that burns at a very hightemperature. Other provides of magnesium incorporate flash photography, flares, and also fireworks. Magnesium is a steel in team 2 that the regular table, i beg your pardon you will certainly read around in this concept.  

The second Group

Barium (Ba) is just one of sixelementsin group 2 the the periodic table, which is shown below. Elements in this team are calledalkaline earth metals. These steels are silver or gray incolor. Castle are reasonably soft and low in density, although no as soft and lightweight together alkali metals. You can watch a brief video clip introduction come the alkaline earth metals at this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.

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Reactivity of Alkaline planet Metals

All alkaline planet metals have comparable properties due to the fact that they all have two valenceelectrons. Castle readily provide up their 2 valence electrons to accomplish a full outerenergy level, i beg your pardon is the most stable setup of electrons. Together a result, castle are an extremely reactive, return not fairly as reactive together the alkali steels in group 1. Because that example, alkaline planet metals will react v coldwater, yet not explosively as alkali metals do. Since of your reactivity, alkaline planet metals never ever exist as puresubstancesin nature. Instead, castle are always found linked with otherelements.

The reactivity that alkaline earth metals boosts from the top to the bottom that the group. That’s due to the fact that theatomsget bigger indigenous the peak to the bottom, for this reason the valenceelectronsare farther indigenous the nucleus. As soon as valence electrons are farther indigenous the nucleus, they space attracted much less strongly through the cell core and more easily gotten rid of from the atom. This makes the atom more reactive.

Q:Alkali metals have actually just one valence electron. Why space alkaline earth metals less reactive than alkali metals?

A:It takes an ext energy to eliminate two valenceelectronsfrom an atom than one valence electron. This makes alkaline planet metals with their 2 valence electrons less reactive than alkali steels with your one valence electron.

Examples of Alkaline earth Metals

For a much better understanding of alkaline earth metals, let’s take a closer look at at two of them: calcium (Ca) and strontium (Sr). Calcium is a soft, gray, nontoxic alkaline earth metal. Although pure calcium doesn’t exist in nature, calciumcompoundsare really common in Earth’s crust and in seawater. Calcium is likewise the many abundant metal in the human body, emerging as calcium compound such as calcium phosphate and also calcium carbonate. This calcium compounds are found in bones and also make them hard and also strong. The skeleton of the typical adult contains about a kilogram of calcium. Because calcium—like barium—absorbs x-rays, bones present up white in x-ray images. Calcium is vital component the a healthy human diet. Good food resources of calcium are pictured inFigurebelow.

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Q:What health difficulties might an outcome from a diet low in calcium?

A:Children that don’t get enough calcium while your bones are developing may construct a deficiency an illness called rickets, in which their bones are softer 보다 normal and become bent and stunted. Adults that don’t get sufficient calcium may develop a condition called osteoporosis, in i m sorry the bones lose calcium and also become weak and also brittle. Civilization with osteoporosis room at high hazard of bone fractures.

Strontium is a silver-colored alkaline planet metal the is even softer than calcium. Strontiumcompoundsare fairly common and have a variety of uses—from fireworks to cement come toothpaste. In fireworks, strontium compounds develop deep red explosions. In toothpaste, prefer the one pictured in theFigurebelow, the compound strontium chloride reduces tooth sensitivity.

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Summary

· elements in group 2 the the periodic table are referred to as alkaline planet metals. They space silvery or gray incolor. They room also reasonably soft and low in density.

· Alkaline earth metals are very reactive because they readily give up their two valence electrons to accomplish a full outerenergy level, i beg your pardon is the most stable setup of electrons. Reactivity boosts from the optimal to the bottom the the group.

· instances of alkaline earth metals include calcium, i beg your pardon is necessary for strong bones, and also strontium, i beg your pardon is supplied for do cement and also other products.

Explore More

At the following URL, observe exactly how four different alkaline planet metals react withwater. ~ you watch the video, price the inquiries below.

http://www.youtube.com/watch?v=B2ZPrg9IVEo(0:16)

1. Observe the reactions in the video, and then location the alkaline earth metals from many to the very least reactive with water.

2. What defines the differences in reactivity?

3. Suspect the reactivity that beryllium v water. Wherein would it fit in your ranking?

4. Whatsubstancesare developed in every reaction that you it was observed in the video?

Review

1. What space alkaline earth metals? What are their physical properties?

2. Why are alkaline planet metals really reactive?

3. Compare and also contrast the reactivity that beryllium (Be) and barium (Ba).

Noble Gases

Characteristics of group 18 of the periodic table.

· recognize the noblegases.

· list properties of noblegases.

· define the nonreactivity that noblegasesand exactly how it is related to theoctet rule.

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Okay, helium balloons space light, however they’re not that light! This fanciful picture serves to do the allude that helium is one of the lightestelements. Helium belongs come a group of elements called the noble gases.

What are Noble Gases?

Noble gasesare nonreactive, nonmetallicelementsin team 18 that the routine table. Together you have the right to see in the routine table inFigurebelow, noble gases incorporate helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and also radon (Rn). All noble gases room colorless and also odorless. They likewise have lowboilingpoints, explaining why they are gases at roomtemperature. Radon, at the bottom that the group, is radioactive, so it constantly decays come otherelements. For fantastic overview of the noble gases, clock the video at this URL:

http://www.youtube.com/watch?v=jdzBRmLsUM8(4:53)

· to learn just how the noble gases were discovered, go to this URL:http://www.youtube.com/watch?v=ceQMs30D16E.

· to explore specific noble gases, click on their signs in the regular table in ~ this URL:http://www.ptable.com/.

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Q:Based on their place in the periodic table (Figureabove), how countless valenceelectronsdo you think noble gases have?

A:The variety of valenceelectronsstarts at one for elements in group 1. It then rises by one native left come right throughout each duration (row) that the regular table for teams 1–2 and also 13–18. Therefore, noble gases have actually eight valence electrons.

Chemical properties of Noble Gases

Noble gases are the least reactive that all known elements. That’s due to the fact that with eight valenceelectrons, their outer power levels space full. The only exception is helium, which has just two electrons. Yet helium additionally has a full outerenergy level, because its only power level (energy level 1) have the right to hold a best of two electrons. A complete outer power level is the most stable arrangement of electrons. Together a result, noble gases cannot become an ext stable by reacting with other elements and gaining or shedding valence electrons. Therefore, noble gases room rarely affiliated inchemical reactionsand nearly never formcompoundswith other elements.

Noble Gases and theOctet Rule

Because the noble gases room the the very least reactive of all elements, their eight valence electrons are offered as the typical for nonreactivity and also to describe how other aspects interact. This is proclaimed as the octet (“group the eight”) rule. According to this rule,atomsreact to formcompoundsthat permit them to have a team of eight valence electrons prefer the noble gases. For example, sodium (with one valence electron) reacts through chlorine (with seven valence electrons) to kind the secure compound sodium chloride (table salt). In this reaction, salt donates an electron and chlorine accepts it, providing each element an octet of valence electrons.

Some uses of Noble Gases

Did you ever get helium balloons prefer those in the opened picture? uneven a balloon filled with air, a balloon filled through helium demands to be weighted under so it won’t float away — although you don’t have to use one elephant!.

Q:Why does a helium balloon float far if it’s no weighted down?

A:Heliumatomshave simply twoprotons, twoneutrons, and two electrons, therefore they have actually less mass than any other atoms other than hydrogen. As a result, helium is lighter than air, explaining why a helium balloon floats up into the air unless weighted down.

Early incandescent irradiate bulbs, favor the one pictured in theFigurebelow, didn’t last really long. The filaments quickly burned out. Return air was pumped out of the bulb, it wasn’t a complete vacuum. Oxygen in the little amount that air continuing to be inside the light pear reacted with the metal filament. This corroded the filament and also caused dark shop on the glass. Pour it until it is full a light bulb through argon gas prevents these problems. That’s why modern light bulbs room filled through argon.

Q:How walk argon prevent the troubles of early on light bulbs?

A:As a noble gas v eight electrons, argon doesn’t react v the metal in the filament. This protects the filament and keeps the glass blub cost-free of deposits.

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Noble gases are also used to to fill the glass tube of lighted indications like the one in theFigurebelow. Back noble gases room chemically nonreactive, your electrons deserve to be energized by sending out anelectric currentthrough them. When this happens, the electrons jump to a higherenergy level. Once the electrons return to their original power level, they give off energy as light. Different noble gases offer off light of different colors. Neon offers off reddish-orange light, choose the word “Open” in the authorize below. Krypton offers off violet light and also xenon provides off blue light.

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Summary

· Noble gases room nonreactive, nonmetallic aspects in team 18 that the routine table.

· Noble gases room the the very least reactive of every elements. That’s since they have actually eight valence electrons, which to fill their outerenergy level. This is the many stable setup of electrons, for this reason noble gases hardly ever react with various other elements and also formcompounds.

· Theoctet rulestates thatatomsreact to form compounds that enable them to have eight valence electrons favor the noble gases, which are the the very least reactive elements.

· Noble gases are offered for balloons, light bulbs, and also lighted signs.

Explore More

Watch the video clip about noble gases at the following URL, and also then price the concerns below.

http://www.open.edu/openlearn/science-maths-technology/science/chemistry/noble-gases

1. Compare and also contrast the reactivity the the elements helium, neon, argon, krypton, and also xenon.

2. To compare the thickness of these noble gases come the thickness of air.

3. Describe how the fixed of noble gases changes from the peak to the bottom of team 18.

Review

1. What room noble gases?

2. Describe why noble gases are almost totally nonreactive.

See more: How Long Does Guacamole Have To Be Refrigerated ? How Long Can Guacamole Sit Out Before It Is Bad

3. What is the octet rule? how is it pertained to noble gases?

4. Hydrogen (H) atoms have actually one electron and exist as diatomic (“two-atom”) molecule (H2). Helium atoms have two electrons and also exist just as single helium atoms. Explain why hydrogen and helium differ in this way.