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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 group 1 the the routine table.

You are watching: Most reactive family on the periodic table

· determine theelementsin group 1 the the regular table.

· explain why group 1elementsare really reactive.

· List various other properties that alkalimetals.

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You most likely think ofwateras a problem that have the right to put out fires. But someelementsare for this reason reactive the they burn in water. In fact, they virtually explode in water. That’s what is continue in the photo above. About 3 pounds of sodium were included to water, and the result was this explosive reaction. Why is salt such a reactive element? In this lesson girlfriend will find out.

The very first Group

Sodium (Na) is an aspect in group 1 the the routine table of the elements. This team (column) the the table is presented below. It consists of the nonmetal hydrogen (H) and also sixmetalsthat space calledalkali metals. Elements in the same team of the routine table have actually the same number of valenceelectrons. These are the electrons in your outerenergy levelthat can be involved in chemistry reactions. Valence electron determine many of the nature of one element, so aspects in the same group have similar properties. Every the facets in group 1 have actually 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, group 1 facets are “eager” to lose that electron. Act so allows them to attain a complete outerenergy leveland preferably stability.

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Reactivity of group 1 Elements

Hydrogen is a really reactive gas, and also the alkalimetalsare even more reactive. In fact, they room the many reactive steels and, together with the aspects in team 17, are the many reactive of all elements. The reactivity that alkali metals boosts from the top to the bottom the the group, for this reason lithium (Li) is the least reactive alkali metal and also francium (Fr) is the most reactive. Since alkali steels are for this reason reactive, lock are uncovered in nature just in combination with various other elements. Lock often incorporate with group 17 elements, i m sorry are very “eager” to get an electron. At the URL below, you have the right to watch a video that shows just how reactive the alkali steels are.

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

Other properties of Alkali Metals

Besides being very reactive, alkali metals share a number of other properties.

· Alkali steels are allsolidsat roomtemperature.

· Alkali metals are short in density, and some of them float onwater.

· Alkali metals are fairly soft. Part are also soft enough to reduced with a knife, like the sodium pictured in theFigurebelow.

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A Closer Look

Although all group 1 aspects share particular properties, such together being very reactive, they room not alike in every way. Three various group 1 aspects are explained in more detail below (Figuresbelow,below, andbelow). Notice the means in which they differ from one another.

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Hydrogen has actually the smallest, lightest atoms of every elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic yet highly flammable. Hydrogen gas exists largely as diatomic (“two-atom”) molecules (H2), as presented in the diagram on the right. Hydrogen is the many abundant facet in the universe and the third most abundant element on Earth, emerging mainly in compounds such together water.


Q:Why execute you think hydrogen gas normally exists together diatomic molecules?

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

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Potassium is a soft, silvery steel that ignites explosively in water. It quickly loses that one valence electron to form positive potassium ions (K+), which are essential by all living cells. Potassium is so crucial for plants the it is found in nearly all fertilizers, choose the one displayed here. Potassium is numerous in Earth’s late in minerals such as feldspar.


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Francium has actually one of the largest, heaviest atoms of every elements. That one valence electron is far removed indigenous the nucleus, as you have the right to see in the atomic design on the right, so the is conveniently removed native the atom. Francium is radioactive and also quickly decays to kind other aspects such together radium. This is why francium is extremely rare in nature. Less than an oz of francium is present on planet at any kind of given time.


Q:Francium decays too easily to formcompoundswith various other elements. Which aspects to girlfriend think it would bond with if it could?

A:With one valence electron, francium would certainly bond with a halogen element in group 17, which has actually seven valenceelectronsand requirements one much more to to fill its outer energy level. Aspects in group 17 include fluorine and also chlorine.

Summary

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

· because they have actually just one valence electron, team 1 facets are very reactive. As a result, lock are discovered in nature just in combination with various other elements.

· Alkali steels are allsolidsat roomtemperature. Castle are reasonably soft and also low in density.

· native the height to the bottom of team 1, the aspects have heavier, much more reactiveatoms.

Explore More

At the adhering to URL, click on “Group 1 data and 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, nature of the alkali metals change as follows:

1. Melting point __________.

2. Boiling allude __________.

3. Density __________.

4. Atom radius __________.

5. Variety of electrons __________.

Review

1. What space alkali metals?

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

3. Define why team 1 facets often formcompoundswith elements in group 17.

4. Compare and contrast hydrogen and also francium.

Alkaline earth Metals

Characteristics of group 2 of the routine table.

· determine alkaline Earthmetals.

· list properties of alkaline Earthmetals.

· define why alkaline Earthmetalsare very reactive.

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Sparklers favor the one this girl is holding make festive additions to plenty of celebrations. You might use lock yourself. Yet watch out if friend do since their flames space really hot! The shining white flames are created when magnesium burns. Magnesium is a light- weight metal that burns in ~ a really hightemperature. Other provides of magnesium incorporate flash photography, flares, and fireworks. Magnesium is a steel in group 2 of the routine table, i m sorry you will certainly read around in this concept.  

The 2nd Group

Barium (Ba) is among sixelementsin team 2 the the routine table, which is presented below. Facets in this group are calledalkaline earth metals. These metals are silver- or gray incolor. Lock are relatively soft and low in density, although not as soft and also lightweight as alkali metals. You deserve to watch a brief video clip introduction come the alkaline earth metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.

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Reactivity that Alkaline earth Metals

All alkaline earth metals have similar properties because they all have two valenceelectrons. They readily offer up their two valence electrons to achieve a complete outerenergy level, i beg your pardon is the most stable arrangement of electrons. Together a result, lock are really reactive, back not quite as reactive as the alkali steels in group 1. Because that example, alkaline earth metals will react with coldwater, however not explosively together alkali steels do. Due to the fact that of your reactivity, alkaline planet metals never ever exist together puresubstancesin nature. Instead, they are constantly found an unified with otherelements.

The reactivity that alkaline earth metals increases from the top to the bottom the the group. That’s since theatomsget bigger indigenous the peak to the bottom, therefore the valenceelectronsare farther indigenous the nucleus. As soon as valence electrons space farther from the nucleus, they space attracted less strongly by the cell core and an ext easily removed from the atom. This makes the atom an ext reactive.

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

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

Examples that Alkaline earth Metals

For a much better understanding the alkaline earth metals, let’s take a closer watch at 2 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 very common in Earth’s crust and in seawater. Calcium is also the many abundant metal in the person body, developing as calcium compound such as calcium phosphate and calcium carbonate. This calcium compound are discovered in bones and also make them hard and strong. The skeleton the the mean adult contains about a kilogram of calcium. Because calcium—like barium—absorbs x-rays, bones display up white in x-ray images. Calcium is crucial component of a healthy human diet. An excellent food sources of calcium are pictured inFigurebelow.

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Q:What health problems might result from a diet low in calcium?

A:Children that don’t get enough calcium while their bones are forming may construct a deficiency an illness called rickets, in which their bones room softer than normal and also become bent and also stunted. Adults who don’t get sufficient calcium may build a condition called osteoporosis, in i m sorry the bones shed calcium and become weak and brittle. World with osteoporosis room at high risk of bone fractures.

Strontium is a silver-colored alkaline earth metal the is also softer than calcium. Strontiumcompoundsare rather common and also have a range of uses—from fireworks come cement come toothpaste. In fireworks, strontium compounds create deep red explosions. In toothpaste, choose the one pictured in theFigurebelow, the compound strontium chloride reduces tooth sensitivity.

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Summary

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

· Alkaline earth metals are really reactive because they readily offer up their 2 valence electron to achieve a complete outerenergy level, i beg your pardon is the most stable plan of electrons. Reactivity increases from the optimal to the bottom of the group.

· examples of alkaline earth metals incorporate calcium, i beg your pardon is essential for solid bones, and strontium, i beg your pardon is supplied for make cement and other products.

Explore More

At the following URL, observe just how four different alkaline earth metals react withwater. After ~ you watch the video, prize the concerns below.

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

1. Watch the reactions in the video, and then location the alkaline earth metals from many to least reactive through water.

2. What describes the distinctions in reactivity?

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

4. Whatsubstancesare produced in each reaction the you it was observed in the video?

Review

1. What space alkaline earth metals? What space their physics properties?

2. Why room alkaline planet metals an extremely reactive?

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

Noble Gases

Characteristics of team 18 of the periodic table.

· identify the noblegases.

· perform properties of noblegases.

· define the nonreactivity of noblegasesand just how it is regarded theoctet rule.

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Okay, helium balloons are light, but they’re no that light! This fanciful photo serves to do the allude that helium is one of the lightestelements. Helium belongs come a team of elements called the noble gases.

What room Noble Gases?

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

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

· come learn exactly how the noble gases to be discovered, walk to this URL:http://www.youtube.com/watch?v=ceQMs30D16E.

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

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Q:Based on their position in the routine table (Figureabove), how plenty of valenceelectronsdo you think noble gases have?

A:The variety of valenceelectronsstarts in ~ one for aspects in team 1. It then boosts by one indigenous left to right across each period (row) the the regular table for groups 1–2 and 13–18. Therefore, noble gases have actually eight valence electrons.

Chemical nature of Noble Gases

Noble gases room the least reactive the all well-known elements. That’s due to the fact that with eight valenceelectrons, your outer energy levels room full. The only exemption is helium, which has actually just two electrons. Yet helium likewise has a complete outerenergy level, because its only energy level (energy level 1) deserve to hold a maximum of 2 electrons. A complete outer power level is the many stable setup of electrons. Together a result, noble gases cannot become more stable by reaction with other elements and also gaining or losing valence electrons. Therefore, noble gases room rarely connected inchemical reactionsand nearly never formcompoundswith various other elements.

Noble Gases and also theOctet Rule

Because the noble gases room the least reactive of all elements, your eight valence electron are offered as the standard for nonreactivity and also to explain how other aspects interact. This is stated as the octet (“group the eight”) rule. Follow to this rule,atomsreact to formcompoundsthat enable them to have actually a team of eight valence electrons favor the noble gases. For example, salt (with one valence electron) reacts through chlorine (with seven valence electrons) to type the stable compound sodium chloride (table salt). In this reaction, salt donates an electron and also chlorine accepts it, offering each aspect an octet of valence electrons.

Some supplies of Noble Gases

Did you ever before get helium balloons choose those in the opening picture? unequal a balloon filled through air, a balloon filled with helium demands to it is in weighted down so that won’t float far — although girlfriend don’t need to use an elephant!.

Q:Why go a helium balloon float away if it’s no weighted down?

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

Early incandescent irradiate bulbs, like the one pictured in theFigurebelow, didn’t last really long. The filaments quickly melted out. Although air was pumped the end of the bulb, that wasn’t a complete vacuum. Oxygen in the little amount the air continuing to be inside the light bulb reacted with the steel filament. This corroded the filament and caused dark store on the glass. Filling a irradiate bulb with argon gas avoids these problems. That’s why modern light bulbs are filled v argon.

Q:How does argon prevent the problems of at an early stage light bulbs?

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

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Noble gases are likewise used to fill the glass pipe of lighted indications like the one in theFigurebelow. Although noble gases room chemically nonreactive, their electrons have the right to be energized by sending out anelectric currentthrough them. When this happens, the electrons run to a higherenergy level. When the electrons go back to their original power level, they give off energy as light. Various noble gases offer off light of various colors. Neon provides off reddish-orange light, choose the indigenous “Open” in the authorize below. Krypton offers off violet light and also xenon gives off blue light.

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Summary

· Noble gases are nonreactive, nonmetallic aspects in team 18 of the periodic table.

· Noble gases room the the very least reactive of all elements. That’s because they have eight valence electrons, which fill their outerenergy level. This is the most stable plan of electrons, for this reason noble gases hardly ever react with other elements and formcompounds.

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

· Noble gases are used for balloons, irradiate bulbs, and also lighted signs.

Explore More

Watch the video clip about noble gases at the adhering to 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 xenon.

2. Compare the density of this noble gases come the density of air.

3. Explain how the fixed of noble gases alters from the height to the bottom of group 18.

Review

1. What space noble gases?

2. Define why noble gases room almost totally nonreactive.

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3. What is the octet rule? exactly how is it concerned noble gases?

4. Hydrogen (H) atoms have actually one electron and exist as diatomic (“two-atom”) molecules (H2). Helium atoms have actually two electrons and exist only as single helium atoms. Define why hydrogen and helium different in this way.