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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 that the routine table.

You are watching: The elements of which group are nonreactive?

· determine theelementsin group 1 the the regular table.

· explain why team 1elementsare very reactive.

· List various other properties the alkalimetals.

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

The first Group

Sodium (Na) is an aspect in group 1 the the periodic table that the elements. This group (column) that the table is displayed below. It has the nonmetal hydrogen (H) and also sixmetalsthat are calledalkali metals. Aspects in the same group of the periodic table have actually the same number of valenceelectrons. These room the electron in your outerenergy levelthat can be associated in chemistry reactions. Valence electron determine countless of the properties of an element, so aspects in the same group have similar properties. All 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 very reactive?

A:With just one valence electron, team 1 aspects are “eager” to shed that electron. Doing so enables them to achieve a full outerenergy leveland preferably 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, together with the elements in group 17, space the most reactive of all elements. The reactivity the alkali metals rises from the height to the bottom that the group, so lithium (Li) is the least reactive alkali metal and francium (Fr) is the many reactive. Due to the fact that alkali metals are so reactive, castle are found in nature only in combination with other elements. They often combine with team 17 elements, i beg your pardon are very “eager” to obtain an electron. At the URL below, you have the right to watch a video clip that reflects just exactly how reactive the alkali steels are.

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

Other properties of Alkali Metals

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

· Alkali steels are allsolidsat roomtemperature.

· Alkali steels are short in density, and also some of castle float onwater.

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

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A Closer Look

Although all group 1 facets share certain properties, such together being very reactive, they space not alike in every way. Three different group 1 facets are defined in more detail listed below (Figuresbelow,below, andbelow). An alert the means in i m sorry they different 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 however highly flammable. Hydrogen gas exists greatly as diatomic (“two-atom”) molecules (H2), as shown in the diagram on the right. Hydrogen is the most abundant facet in the universe and also the third most abundant aspect on Earth, occurring mainly in compound such together water.


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

A:Each hydrogen atom has just one electron. Once two hydrogenatomsbond together, castle share a pair ofelectrons. The shared electrons fill their onlyenergy level, giving them the many stable setup of electrons.

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


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Francium has one of the largest, heaviest atom of every elements. That one valence electron is much removed native the nucleus, together you have the right to see in the atomic design on the right, so it is easily removed from the atom. Francium is radioactive and also quickly decays to type other elements such together radium. This is why francium is exceptionally rare in nature. Much less than an oz of francium is existing on earth at any type of given time.


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

A:With one valence electron, francium would bond v a halogen facet in group 17, which has seven valenceelectronsand demands one an ext to fill its outer energy level. Elements in group 17 include fluorine and also chlorine.

Summary

· group 1 of the periodic table contains hydrogen and the alkali metals.

· because they have actually just one valence electron, team 1 elements are really reactive. Together a result, castle are found in nature just in combination with various other elements.

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

· native the height to the bottom of group 1, the elements have heavier, more reactiveatoms.

Explore More

At the following URL, click “Group 1 data and 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 optimal to the bottom of group 1, nature of the alkali metals change as follows:

1. Melting allude __________.

2. Boiling point __________.

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 aspects in team 17.

4. Compare and also contrast hydrogen and also francium.

Alkaline earth Metals

Characteristics of group 2 the the routine table.

· identify alkaline Earthmetals.

· list properties the alkaline Earthmetals.

· describe why alkaline Earthmetalsare very reactive.

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Sparklers favor the one this girl is holding do festive additions to many celebrations. You may use castle yourself. But watch out if you do since their flames are really hot! The bright white flames are developed when magnesium burns. Magnesium is a light- weight metal that burns in ~ a really hightemperature. Other provides of magnesium encompass flash photography, flares, and fireworks. Magnesium is a steel in group 2 of the periodic table, which you will read around in this concept.  

The second Group

Barium (Ba) is one of sixelementsin team 2 the the regular table, i beg your pardon is shown below. Elements in this team are calledalkaline planet metals. These steels are silver or gray incolor. Lock are fairly soft and low in density, although not as soft and lightweight together alkali metals. You deserve to watch a brief video introduction to the alkaline planet metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.

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Reactivity of Alkaline planet Metals

All alkaline earth metals have similar properties due to the fact that they all have two valenceelectrons. Lock readily offer up their 2 valence electron to accomplish a complete outerenergy level, i beg your pardon is the many stable plan of electrons. As a result, lock are very reactive, although not fairly as reactive together the alkali metals in team 1. Because that example, alkaline planet metals will certainly react with coldwater, yet not explosively as alkali steels do. Due to the fact that of your reactivity, alkaline earth metals never exist as puresubstancesin nature. Instead, they are constantly found combined with otherelements.

The reactivity the alkaline planet metals increases from the optimal to the bottom the the group. That’s due to the fact that theatomsget bigger from the optimal to the bottom, therefore the valenceelectronsare farther native the nucleus. Once valence electrons space farther indigenous the nucleus, they are attracted less strongly by the cell nucleus and an ext easily eliminated from the atom. This renders the atom much more reactive.

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

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

Examples of Alkaline planet Metals

For a far better understanding that alkaline planet metals, let’s take a closer look at two of them: calcium (Ca) and also strontium (Sr). Calcium is a soft, gray, nontoxic alkaline earth metal. Return pure calcium doesn’t exist in nature, calciumcompoundsare really common in Earth’s crust and in seawater. Calcium is also the many abundant steel in the human body, emerging as calcium link such together calcium phosphate and also calcium carbonate. These calcium link are discovered in bones and make castle hard and strong. The skeleton the the median adult contains around a kilogram that calcium. Since calcium—like barium—absorbs x-rays, bones display up white in x-ray images. Calcium is crucial component the a healthy human diet. Great food resources of calcium are pictured inFigurebelow.

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Q:What health difficulties might result from a diet short in calcium?

A:Children who don’t get sufficient calcium while your bones are forming may construct a deficiency disease called rickets, in which your bones are softer 보다 normal and 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 also brittle. Civilization with osteoporosis are at high danger of bone fractures.

Strontium is a silver-colored alkaline planet metal the is even softer 보다 calcium. Strontiumcompoundsare quite common and also have a range of uses—from fireworks come cement to toothpaste. In fireworks, strontium compounds develop deep red explosions. In toothpaste, choose the one pictured in theFigurebelow, the link strontium chloride reduces this sensitivity.

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Summary

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

· Alkaline earth metals are very reactive since they readily provide up their 2 valence electron to achieve a full outerenergy level, i beg your pardon is the most stable arrangement of electrons. Reactivity rises from the peak to the bottom the the group.

· instances of alkaline earth metals encompass calcium, i m sorry is required for strong bones, and also strontium, i m sorry is used for making cement and other products.

Explore More

At the following URL, observe just how four various alkaline planet metals react withwater. ~ you watch the video, prize the questions below.

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

1. Observe the reaction in the video, and also then location the alkaline planet metals from many to least reactive v water.

2. What describes the distinctions in reactivity?

3. Suspect the reactivity the beryllium with water. Where would that fit in your ranking?

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

Review

1. What room alkaline planet metals? What room their physics properties?

2. Why are alkaline earth metals really reactive?

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

Noble Gases

Characteristics of team 18 of the routine table.

· determine the noblegases.

· list properties that noblegases.

· explain the nonreactivity the noblegasesand how it is concerned theoctet rule.

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Okay, helium balloons room light, but they’re not that light! This fanciful photo serves to make the suggest that helium is among the lightestelements. Helium belongs come a group of aspects called the noble gases.

What are Noble Gases?

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

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

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

· come explore certain noble gases, click their symbols in the periodic table at this URL:http://www.ptable.com/.

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

A:The variety of valenceelectronsstarts in ~ one for aspects in group 1. The then rises by one indigenous left come right across each period (row) that the periodic table for groups 1–2 and also 13–18. Therefore, noble gases have actually eight valence electrons.

Chemical nature of Noble Gases

Noble gases space the the very least reactive that all well-known elements. That’s due to the fact that with eight valenceelectrons, their outer energy levels space full. The only exemption is helium, which has just 2 electrons. But helium likewise has a full outerenergy level, due to the fact that its only power level (energy level 1) deserve to hold a preferably of 2 electrons. A full outer power level is the most stable setup of electrons. As a result, noble gases cannot become much more stable by reacting with other elements and also gaining or shedding valence electrons. Therefore, noble gases are rarely involved inchemical reactionsand practically never formcompoundswith other elements.

Noble Gases and also theOctet Rule

Because the noble gases room the the very least reactive of all elements, their eight valence electrons are supplied as the conventional for nonreactivity and also to describe how other facets interact. This is declared as the octet (“group the eight”) rule. Follow to this rule,atomsreact to formcompoundsthat enable them to have actually a group of eight valence electrons prefer the noble gases. Because that example, salt (with one valence electron) reacts v chlorine (with seven valence electrons) to kind the steady compound salt chloride (table salt). In this reaction, sodium donates an electron and chlorine accepts it, offering each element an octet that valence electrons.

Some supplies of Noble Gases

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

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

A:Heliumatomshave simply twoprotons, twoneutrons, and also two electrons, so they have less fixed than any type of other atoms other than 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 irradiate bulbs, favor the one pictured in theFigurebelow, didn’t last an extremely long. The filaments quickly melted out. Although air was pumped the end of the bulb, it wasn’t a finish vacuum. Oxygen in the small amount of air continuing to be inside the light bulb reacted v the metal filament. This corroded the filament and caused dark store on the glass. Filling a irradiate bulb through argon gas avoids these problems. That’s why modern light bulbs are filled through argon.

Q:How walk argon avoid the troubles of beforehand light bulbs?

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

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Noble gases are additionally used to fill the glass tubes of lighted indications like the one in theFigurebelow. Although noble gases room chemically nonreactive, their electrons can be energized by sending out anelectric currentthrough them. Once this happens, the electrons jump to a higherenergy level. As soon as the electrons return to their original energy level, they give off energy as light. Various noble gases give off irradiate of various colors. Neon offers off reddish-orange light, choose the indigenous “Open” in the authorize below. Krypton provides off violet light and xenon provides off blue light.

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Summary

· Noble gases space nonreactive, nonmetallic aspects in group 18 the the periodic table.

· Noble gases are the the very least reactive of all elements. That’s due to the fact that they have eight valence electrons, which to fill their outerenergy level. This is the most stable setup of electrons, so noble gases hardly ever react with various other elements and also formcompounds.

· Theoctet rulestates thatatomsreact to kind compounds that permit them to have eight valence electrons choose the noble gases, which are the least reactive elements.

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

Explore More

Watch the video about noble gases in ~ the adhering to URL, and also then price the inquiries 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. Compare the density of this noble gases come the density of air.

3. Explain how the massive of noble gases changes from the optimal to the bottom of group 18.

Review

1. What space noble gases?

2. Explain why noble gases space almost totally nonreactive.

See more: How Many Cups In A Chicken Breast, How Many Chicken Breasts In A Cup

3. What is the octet rule? exactly 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 only as solitary helium atoms. Describe why hydrogen and also helium differ in this way.