assignments unit 3 component 3

Hydrogen and also alkali metals

Alkali earth metals

Nobel gases

Hydrogen and also Alkali Metals

Characteristics of team 1 of the periodic table.

You are watching: Most reactive element in group 1

· recognize theelementsin group 1 of the routine table.

· define why group 1elementsare very reactive.

· List various other properties that alkalimetals.


You probably 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 happening 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 find out.

The very first Group

Sodium (Na) is an aspect in team 1 that the periodic table that the elements. This team (column) of the table is presented below. It has the nonmetal hydrogen (H) and also sixmetalsthat are calledalkali metals. Aspects in the same group of the periodic table have the same variety of valenceelectrons. These room the electrons in their outerenergy levelthat can be associated in chemistry reactions. Valence electron determine plenty of of the nature of an element, so aspects in the same group have comparable properties. Every the elements in team 1 have actually just one valence electron. This provides them really reactive.

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

A:With simply one valence electron, group 1 elements are “eager” to lose that electron. Doing so enables them to achieve a full outerenergy leveland maximum stability.


Reactivity of group 1 Elements

Hydrogen is a very reactive gas, and also the alkalimetalsare even an ext reactive. In fact, they are the most reactive metals and, together with the elements in team 17, are the many reactive of all elements. The reactivity that alkali metals increases from the height to the bottom the the group, so lithium (Li) is the least reactive alkali metal and also francium (Fr) is the most reactive. Since alkali steels are for this reason reactive, castle are discovered in nature only in mix with other elements. Lock often integrate with group 17 elements, i beg your pardon are an extremely “eager” to obtain an electron. At the URL below, you deserve to watch a video that mirrors just just how reactive the alkali metals are.


Other properties of Alkali Metals

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

· Alkali steels are allsolidsat roomtemperature.

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

· Alkali steels are relatively soft. Some are also soft enough to cut with a knife, favor the salt pictured in theFigurebelow.


A Closer Look

Although all group 1 elements share specific properties, such as being an extremely reactive, they space not alike in every way. Three various group 1 facets are explained in much more detail listed below (Figuresbelow,below, andbelow). Notification the means in i beg your pardon they differ from one another.


Hydrogen has actually the smallest, lightest atoms of all 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 diagram on the right. Hydrogen is the most abundant aspect in the universe and also the 3rd most abundant element on Earth, occurring mainly in link such as water.

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

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


Potassium is a soft, silvery metal that ignites explosively in water. It quickly loses that is one valence electron to type positive potassium ion (K+), i m sorry are necessary by all living cells. Potassium is so essential for plants that it is uncovered in nearly all fertilizers, favor the one presented here. Potassium is plentiful in Earth’s late in minerals such together feldspar.


Francium has one of the largest, heaviest atoms of every elements. That is one valence electron is far removed indigenous the nucleus, together you have the right to see in the atomic model on the right, so it is quickly removed native 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 ounce of francium is present on planet at any type of given time.

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

A:With one valence electron, francium would bond v a halogen element in team 17, which has seven valenceelectronsand needs one an ext to fill its outer energy level. Facets in team 17 incorporate fluorine and chlorine.


· group 1 the the regular table contains hydrogen and the alkali metals.

· since they have actually just one valence electron, group 1 facets are very reactive. Together a result, lock are discovered in nature only in combination with various other elements.

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

· indigenous the top to the bottom of team 1, the elements have heavier, much more reactiveatoms.

Explore More

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


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. Number of electrons __________.


1. What are alkali metals?

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

3. Define why team 1 elements often formcompoundswith aspects in team 17.

4. Compare and contrast hydrogen and also francium.

Alkaline earth Metals

Characteristics of team 2 the the periodic table.

· recognize alkaline Earthmetals.

· list properties that alkaline Earthmetals.

· describe why alkaline Earthmetalsare really reactive.


Sparklers favor the one this girl is holding make festive enhancements to many celebrations. You might use lock yourself. But watch out if you do because their flames space really hot! The shining white flames are created when magnesium burns. Magnesium is a light- weight metal that burns at a very hightemperature. Other supplies of magnesium incorporate flash photography, flares, and also fireworks. Magnesium is a metal in group 2 of the periodic table, i beg your pardon you will certainly read around in this concept.  

The 2nd Group

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


Reactivity of Alkaline earth Metals

All alkaline earth metals have similar properties due to the fact that they all have actually two valenceelectrons. They readily provide up their 2 valence electron to accomplish a complete outerenergy level, which is the many stable arrangement of electrons. Together a result, castle are very reactive, return not rather as reactive together the alkali steels in group 1. Because that example, alkaline planet metals will certainly react v coldwater, but not explosively together alkali metals do. Due to the fact that of your reactivity, alkaline planet metals never exist together puresubstancesin nature. Instead, they are always found linked with otherelements.

The reactivity of alkaline planet metals boosts from the peak to the bottom that the group. That’s since theatomsget bigger from the optimal to the bottom, therefore the valenceelectronsare farther native the nucleus. Once valence electrons space farther native the nucleus, they are attracted much less strongly through the nucleus and an ext easily eliminated from the atom. This makes the atom much more reactive.

Q:Alkali metals have actually just one valence electron. Why room 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 earth metals v their two valence electrons much less reactive than alkali steels with their one valence electron.

Examples that Alkaline earth Metals

For a far better understanding that alkaline planet metals, let’s take a closer look at at two 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 most abundant steel in the human being body, arising as calcium compounds such as calcium phosphate and calcium carbonate. These calcium compound are discovered in bones and make castle hard and also strong. The skeleton the the typical adult contains around a kilogram the calcium. Since calcium—like barium—absorbs x-rays, bones present up white in x-ray images. Calcium is an important component of a healthy and balanced human diet. Good food sources of calcium room pictured inFigurebelow.


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

A:Children who don’t get enough calcium while your bones are developing may construct a deficiency disease called rickets, in which their bones room softer than normal and become bent and stunted. Adults who don’t get sufficient calcium may construct a problem called osteoporosis, in which the bones lose calcium and also become weak and also brittle. Civilization with osteoporosis are at high threat of bone fractures.

Strontium is a silver-colored alkaline earth metal the is also softer than calcium. Strontiumcompoundsare fairly common and also have a variety of uses—from fireworks to cement come toothpaste. In fireworks, strontium compounds produce deep red explosions. In toothpaste, like the one pictured in theFigurebelow, the link strontium chloride reduces this sensitivity.



· facets in group 2 of the regular table are dubbed alkaline earth metals. They are silvery or gray incolor. They are also reasonably soft and low in density.

· Alkaline earth metals are really reactive since they readily give up their 2 valence electron to achieve a full outerenergy level, which is the most stable setup of electrons. Reactivity rises from the top to the bottom the the group.

· examples of alkaline earth metals incorporate calcium, i beg your pardon is required for strong bones, and also strontium, which is used for make cement and also other products.

Explore More

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


1. Watch the reaction in the video, and also then rank the alkaline planet metals from most to the very least reactive through water.

2. What describes the differences in reactivity?

3. Suspect the reactivity that beryllium v water. Whereby would it fit in her ranking?

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


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

2. Why space alkaline earth metals really reactive?

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

Noble Gases

Characteristics of group 18 that the regular table.

· identify the noblegases.

· list properties that noblegases.

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


Okay, helium balloons room light, yet they’re no that light! This fanciful snapshot serves to do the point that helium is just one of the lightestelements. Helium belongs come a group of elements called the noble gases.

What are Noble Gases?

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


· to learn just 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 symbols in the periodic table at this URL:http://www.ptable.com/.


Q:Based top top their place in the routine table (Figureabove), how numerous valenceelectronsdo girlfriend think noble gases have?

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

Chemical nature of Noble Gases

Noble gases space the the very least reactive of all known elements. That’s due to the fact that with eight valenceelectrons, your outer energy levels are full. The only exemption is helium, which has just two electrons. But helium likewise has a complete outerenergy level, due to the fact that its only power level (energy level 1) have the right to hold a preferably of two electrons. A complete outer power level is the most stable plan of electrons. Together a result, noble gases can not become an ext stable by reaction with other elements and gaining or losing valence electrons. Therefore, noble gases room rarely associated inchemical reactionsand almost never formcompoundswith other elements.

Noble Gases and also theOctet Rule

Because the noble gases are the least reactive of all elements, your eight valence electrons are supplied as the traditional for nonreactivity and to describe 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. Because that example, salt (with one valence electron) reacts through chlorine (with 7 valence electrons) to kind the stable compound sodium chloride (table salt). In this reaction, salt donates an electron and also chlorine accepts it, offering each facet an octet the valence electrons.

Some offers of Noble Gases

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

Q:Why walk a helium balloon float away if it’s not weighted down?

A:Heliumatomshave simply twoprotons, twoneutrons, and two electrons, for this reason they have actually 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 light bulbs, favor the one pictured in theFigurebelow, didn’t last an extremely long. The filaments quickly burned out. Although air was pumped out of the bulb, it wasn’t a complete vacuum. Oxygen in the tiny amount of air remaining inside the light bulb reacted v the steel filament. This corroded the filament and also caused dark deposits on the glass. Filling a irradiate bulb with argon gas prevents these problems. That’s why contemporary light bulbs are filled v argon.

Q:How does argon protect against the problems of early on light bulbs?

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


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



· Noble gases are nonreactive, nonmetallic facets in team 18 the the regular table.

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

· Theoctet rulestates thatatomsreact to kind compounds that permit them to have actually 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 about noble gases at the adhering to URL, and also then price the questions below.


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

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

3. Describe how the fixed of noble gases alters from the peak to the bottom of group 18.


1. What space noble gases?

2. Explain why noble gases are almost completely nonreactive.

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

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