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assignments unit 3 component 3

Hydrogen and also alkali metals

Alkali planet metals

Nobel gases

Hydrogen and also Alkali Metals

Characteristics of team 1 of the periodic table.

You are watching: Which family of elements in the periodic table contains the most reactive metals

· identify theelementsin team 1 that the routine table.

· explain why group 1elementsare very reactive.

· List various other properties of alkalimetals.

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

The very first Group

Sodium (Na) is an facet in group 1 the the routine table of the elements. This group (column) that the table is presented below. It consists of the nonmetal hydrogen (H) and also sixmetalsthat are calledalkali metals. Elements in the same team of the regular table have actually the same number of valenceelectrons. These space the electrons in their outerenergy levelthat deserve to be affiliated in chemical reactions. Valence electron determine plenty of of the properties of an element, so elements in the same team have similar properties. Every the aspects in group 1 have just one valence electron. This renders them really reactive.

Q:Why does having just one valence electron make team 1 elements an extremely reactive?

A:With simply one valence electron, group 1 facets are “eager” to shed that electron. Law so allows them to accomplish a full outerenergy leveland preferably stability.

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Reactivity of team 1 Elements

Hydrogen is a an extremely reactive gas, and the alkalimetalsare even much more reactive. In fact, they room the many reactive metals and, together with the elements in group 17, are the many reactive of every elements. The reactivity that alkali metals rises from the height to the bottom that the group, therefore lithium (Li) is the the very least reactive alkali metal and francium (Fr) is the many reactive. Since alkali steels are for this reason reactive, they are uncovered in nature just in combination with various other elements. Castle often combine with group 17 elements, i m sorry are very “eager” to get an electron. In ~ the URL below, you can watch a video that shows just just how reactive the alkali metals are.

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

Other nature of Alkali Metals

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

· Alkali metals are allsolidsat roomtemperature.

· Alkali metals are low in density, and also some of castle float onwater.

· Alkali steels are relatively soft. Part are even soft enough to cut with a knife, prefer the sodium pictured in theFigurebelow.

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A Closer Look

Although all group 1 elements share certain properties, such together being very reactive, they room not alike in every way. Three various group 1 aspects are explained in an ext detail below (Figuresbelow,below, andbelow). Notice the methods in i beg your pardon they different from one another.

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Hydrogen has the smallest, lightest atom of all elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic however 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, developing mainly in compound such as water.


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

A:Each hydrogen atom has just one electron. Once two hydrogenatomsbond together, they share a pair ofelectrons. The mutual electrons fill their onlyenergy level, providing them the most stable plan of electrons.

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Potassium is a soft, silvery steel that ignites explosively in water. It quickly loses that is one valence electron to kind positive potassium ions (K+), which are needed by all living cells. Potassium is so necessary for plants the it is found in practically all fertilizers, prefer the one shown here. Potassium is numerous in Earth’s crust in minerals such as feldspar.


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Francium has actually one the the largest, heaviest atom of all elements. That one valence electron is much removed native the nucleus, as you can see in the atomic version on the right, so that is conveniently removed native the atom. Francium is radioactive and also quickly decays to type other elements such together radium. This is why francium is extremely rare in nature. Less than an ounce of francium is current on planet at any type of given time.


Q:Francium decays too quickly to formcompoundswith other elements. Which aspects to friend think it would bond through if it could?

A:With one valence electron, francium would bond through a halogen element in group 17, which has seven valenceelectronsand requirements one an ext to to fill its outer energy level. Elements in team 17 encompass fluorine and chlorine.

Summary

· group 1 that the routine table contains hydrogen and the alkali metals.

· since they have actually just one valence electron, team 1 elements are an extremely reactive. As a result, castle are found in nature only in combination with various other elements.

· Alkali metals are allsolidsat roomtemperature. They are reasonably soft and low in density.

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

Explore More

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

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

From the top to the bottom of group 1, properties of the alkali metals readjust as follows:

1. Melting point __________.

2. Boiling suggest __________.

3. Density __________.

4. Atomic radius __________.

5. Number of electrons __________.

Review

1. What are alkali metals?

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

3. Describe why team 1 aspects often formcompoundswith facets in team 17.

4. Compare and contrast hydrogen and francium.

Alkaline earth Metals

Characteristics of team 2 of the periodic table.

· determine alkaline Earthmetals.

· perform properties the alkaline Earthmetals.

· explain why alkaline Earthmetalsare really reactive.

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Sparklers prefer the one this girl is holding do festive enhancements to plenty of celebrations. You might use castle yourself. But watch the end if girlfriend do because their flames room really hot! The shining white flames are produced when magnesium burns. Magnesium is a light- weight metal that burns at a very hightemperature. Other provides of magnesium incorporate flash photography, flares, and fireworks. Magnesium is a steel in group 2 the the periodic table, i beg your pardon you will certainly read about in this concept.  

The second Group

Barium (Ba) is just one of sixelementsin team 2 of the routine table, i beg your pardon is presented below. Facets in this team are calledalkaline earth metals. These metals are silver- or gray incolor. They are reasonably soft and also low in density, although not as soft and also lightweight together alkali metals. You deserve to watch a brief video introduction come the alkaline earth metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.

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Reactivity the Alkaline planet Metals

All alkaline planet metals have similar properties due to the fact that they all have actually two valenceelectrons. They readily provide up their 2 valence electrons to achieve a complete outerenergy level, i m sorry is the many stable plan of electrons. Together a result, castle are very reactive, although not quite as reactive as the alkali metals in team 1. Because that example, alkaline earth metals will react through coldwater, however not explosively as alkali steels do. Since of your reactivity, alkaline planet metals never ever exist as puresubstancesin nature. Instead, lock are constantly found an unified with otherelements.

The reactivity that alkaline planet metals increases from the optimal to the bottom of the group. That’s since theatomsget bigger from the optimal to the bottom, for this reason the valenceelectronsare farther native the nucleus. As soon as valence electrons room farther indigenous the nucleus, they are attracted much less strongly by the cell nucleus and more easily removed from the atom. This renders the atom much more reactive.

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

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

Examples that Alkaline planet Metals

For a better understanding of alkaline earth metals, let’s take a closer look at at 2 of them: calcium (Ca) and also strontium (Sr). Calcium is a soft, gray, nontoxic alkaline planet metal. Return pure calcium doesn’t exist in nature, calciumcompoundsare really common in Earth’s crust and also in seawater. Calcium is also the many abundant metal in the human being body, developing as calcium compounds such as calcium phosphate and also calcium carbonate. This calcium compounds are found in bones and make lock hard and strong. The skeleton of the mean adult contains around a kilogram the calcium. Because calcium—like barium—absorbs x-rays, bones show up white in x-ray images. Calcium is an essential component the a healthy human diet. An excellent food resources of calcium room pictured inFigurebelow.

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

A:Children that don’t get sufficient calcium while their bones are developing may construct a deficiency condition called rickets, in which their bones space softer than normal and also become bent and stunted. Adults that don’t get sufficient calcium may construct a problem called osteoporosis, in i m sorry the bones shed 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 also softer 보다 calcium. Strontiumcompoundsare fairly common and have a selection of uses—from fireworks come cement to toothpaste. In fireworks, strontium compounds produce deep red explosions. In toothpaste, prefer the one pictured in theFigurebelow, the link strontium chloride reduces this sensitivity.

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Summary

· aspects in team 2 that the routine table are dubbed alkaline earth metals. They room silvery or gray incolor. They are also relatively soft and low in density.

· Alkaline planet metals are an extremely reactive because they readily offer up their 2 valence electron to achieve a complete outerenergy level, which is the most stable plan of electrons. Reactivity increases from the optimal to the bottom of the group.

· examples of alkaline earth metals encompass calcium, which is essential for strong bones, and also strontium, i beg your pardon is offered for do cement and other products.

Explore More

At the complying with URL, observe exactly how four various alkaline planet metals reaction withwater. After you watch the video, prize the concerns below.

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

1. Observe the reaction in the video, and then rank the alkaline earth metals from many to the very least reactive through water.

2. What defines the differences in reactivity?

3. Guess the reactivity of beryllium with water. Where would it fit in her ranking?

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

Review

1. What space alkaline planet metals? What room their physical properties?

2. Why are alkaline earth metals very reactive?

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

Noble Gases

Characteristics of team 18 that the periodic table.

· recognize the noblegases.

· list properties the noblegases.

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

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Okay, helium balloons space light, but they’re no that light! This fanciful picture serves to do the suggest that helium is one of the lightestelements. Helium belongs to a team of aspects called the noble gases.

What space Noble Gases?

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

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

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

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

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Q:Based top top their place in the periodic table (Figureabove), how many valenceelectronsdo friend think noble gases have?

A:The number of valenceelectronsstarts at one for facets in group 1. It then boosts by one native left come right across each period (row) of the periodic table for groups 1–2 and also 13–18. Therefore, noble gases have actually eight valence electrons.

Chemical properties of Noble Gases

Noble gases space the least reactive that all recognized elements. That’s because with eight valenceelectrons, their outer energy levels space full. The only exemption is helium, which has actually just two electrons. Yet helium additionally has a full outerenergy level, due to the fact that its only power level (energy level 1) have the right to hold a maximum of two electrons. A complete outer energy level is the most stable arrangement of electrons. As a result, noble gases cannot become much more stable by reaction with various other elements and gaining or losing valence electrons. Therefore, noble gases room rarely connected inchemical reactionsand practically never formcompoundswith various other elements.

Noble Gases and also theOctet Rule

Because the noble gases are the the very least reactive of every elements, your eight valence electrons are provided as the standard for nonreactivity and to define how other aspects interact. This is declared as the octet (“group of eight”) rule. According to this rule,atomsreact come formcompoundsthat allow them to have a group of eight valence electrons like the noble gases. For example, sodium (with one valence electron) reacts v chlorine (with seven valence electrons) to form the secure compound sodium chloride (table salt). In this reaction, sodium donates one electron and also chlorine accepts it, providing each aspect an octet of valence electrons.

Some offers of Noble Gases

Did you ever before get helium balloons choose those in the opening picture? uneven a balloon filled v air, a balloon filled v helium demands to be weighted under so the won’t float far — although you don’t have to use an elephant!.

Q:Why go a helium balloon float far if it’s not weighted down?

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

Early incandescent light bulbs, choose the one pictured in theFigurebelow, didn’t last very long. The filaments quickly shed out. Return air to be pumped the end of the bulb, it wasn’t a complete vacuum. Oxygen in the little amount the air continuing to be inside the light pear reacted v the steel filament. This corroded the filament and caused dark shop on the glass. Pour it until it is full a light bulb through argon gas stays clear of these problems. That’s why modern light bulbs space filled through argon.

Q:How does argon stop the difficulties of beforehand 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 free of deposits.

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Noble gases are likewise used to fill the glass tube of lighted indications like the one in theFigurebelow. Return noble gases room chemically nonreactive, their electrons can be energized by sending out anelectric currentthrough them. Once this happens, the electrons run to a higherenergy level. When the electrons return to their original energy level, they provide off power as light. Various noble gases give off light of different colors. Neon gives off reddish-orange light, like the native “Open” in the sign below. Krypton offers off violet light and also xenon provides off blue light.

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Summary

· Noble gases space nonreactive, nonmetallic elements in group 18 the the regular table.

· Noble gases space the the very least reactive of all elements. That’s since they have actually eight valence electrons, which to fill their outerenergy level. This is the most stable plan of electrons, therefore noble gases rarely react with other elements and also formcompounds.

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

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

Explore More

Watch the video clip about noble gases at the complying with URL, and also then answer the concerns below.

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

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

2. To compare the density of these noble gases to the thickness of air.

3. Explain how the mass of noble gases changes from the top to the bottom of team 18.

Review

1. What are noble gases?

2. Define why noble gases room almost totally nonreactive.

See more: What Road Does The Muffin Man Live On, The Muffin Man

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

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