Caufdercouch.net.org

assignments --> unit 3 part 3 --> hydrogen and alkali metals

assignments --> unit 3 component 3 --> alkali earth metals

assignments --> unit 3 component 3 --> nobel gases

COMPUTERS - practice until 100%

NO computers - write questions and also answers to the review questions

Hydrogen and Alkali Metals

Characteristics of group 1 that the routine table.

You are watching: Alkali metals have how many valence electrons

· identify theelementsin team 1 the the periodic table.

· define why team 1elementsare very reactive.

· List other properties of alkalimetals.

*

You probably think ofwateras a substance that can put the end fires. Yet someelementsare therefore reactive the they burn in water. In fact, they essentially explode in water. That’s what is continue in the picture above. About 3 pounds of sodium were included to water, and the an outcome was this explosive reaction. Why is salt such a reactive element? In this lesson you will uncover out.

The very first Group

Sodium (Na) is an element in group 1 of the routine table that the elements. This group (column) of the table is shown below. It has the nonmetal hydrogen (H) and also sixmetalsthat space calledalkali metals. Elements in the same group of the regular table have the same variety of valenceelectrons. These room the electrons in their outerenergy levelthat have the right to be connected in chemical reactions. Valence electrons determine many of the properties of one element, so elements in the same group have comparable properties. All the elements in group 1 have just one valence electron. This renders them really reactive.

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

A:With simply one valence electron, group 1 facets are “eager” to shed that electron. Doing so enables them to attain a complete outerenergy leveland preferably stability.

*

Reactivity of team 1 Elements

Hydrogen is a very reactive gas, and also the alkalimetalsare even an ext reactive. In fact, they space the many reactive steels and, in addition to the facets in team 17, room the many reactive of every elements. The reactivity the alkali metals increases from the optimal to the bottom of the group, so lithium (Li) is the the very least reactive alkali metal and francium (Fr) is the many reactive. Because alkali steels are so reactive, lock are found in nature only in combination with various other elements. Lock often integrate with group 17 elements, i m sorry are an extremely “eager” to acquire an electron. At the URL below, you deserve to watch a video clip that shows just exactly how reactive the alkali steels are.

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

Other properties of Alkali Metals

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

· Alkali steels are allsolidsat roomtemperature.

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

· Alkali steels are reasonably soft. Part are even soft enough to reduced 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 different group 1 aspects are defined in an ext detail listed below (Figuresbelow,below, andbelow). Notice the means in which they different from one another.

*


Hydrogen has actually the smallest, lightest atom of all elements. Pure hydrogen is a colorless, odorless, tasteless gas that is nontoxic but highly flammable. Hydrogen gas exists mostly as diatomic (“two-atom”) molecule (H2), as displayed in the chart on the right. Hydrogen is the many abundant facet in the universe and also the 3rd most abundant element on Earth, occurring mainly in link such together water.


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

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

*


Potassium is a soft, silvery steel that ignites explosively in water. It quickly loses its one valence electron to kind positive potassium ions (K+), i beg your pardon are essential by all living cells. Potassium is so vital for plants that it is discovered in nearly all fertilizers, choose the one displayed here. Potassium is numerous in Earth’s crust in minerals such together feldspar.


*


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


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

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

Summary

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

· since they have just one valence electron, group 1 facets are really reactive. As a result, castle are uncovered in nature only in mix with various other elements.

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

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

Explore More

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

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

From the optimal to the bottom of group 1, nature of the alkali metals readjust as follows:

1. Melting suggest __________.

2. Boiling point __________.

3. Density __________.

4. Atomic radius __________.

5. Number of electrons __________.

Review

1. What room 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 also contrast hydrogen and francium.

Alkaline planet Metals

Characteristics of group 2 that the regular table.

· identify alkaline Earthmetals.

· perform properties of alkaline Earthmetals.

· explain why alkaline Earthmetalsare very reactive.

*

Sparklers choose the one this girl is holding make festive additions to plenty of celebrations. You might use lock yourself. However watch the end if friend do because their flames are really hot! The bright white flames are created when magnesium burns. Magnesium is a light- weight steel that burns at a very hightemperature. Other offers of magnesium encompass flash photography, flares, and fireworks. Magnesium is a metal in team 2 of the routine table, i beg your pardon you will certainly read about in this concept.  

The second Group

Barium (Ba) is among sixelementsin group 2 of the periodic table, i beg your pardon is displayed 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 have the right to watch a brief video introduction to the alkaline earth metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.

*

Reactivity of Alkaline planet Metals

All alkaline earth metals have similar properties because they all have two valenceelectrons. Castle readily offer up their two valence electrons to attain a complete outerenergy level, i m sorry is the most stable arrangement of electrons. Together a result, they are an extremely reactive, back not rather as reactive as the alkali metals in group 1. Because that example, alkaline planet metals will react v coldwater, but not explosively as alkali steels do. Since of your reactivity, alkaline earth metals never exist as puresubstancesin nature. Instead, they are constantly found merged with otherelements.

The reactivity the alkaline planet metals increases from the top to the bottom of the group. That’s due to the fact that theatomsget bigger native the optimal to the bottom, so the valenceelectronsare farther from the nucleus. As soon as valence electrons space farther from the nucleus, they room attracted less strongly by the nucleus and more easily eliminated from the atom. This provides the atom more reactive.

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

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

Examples of Alkaline planet Metals

For a much better understanding of alkaline earth metals, let’s take a closer look at at 2 of them: calcium (Ca) and strontium (Sr). Calcium is a soft, gray, nontoxic alkaline earth metal. Return pure calcium doesn’t exist in nature, calciumcompoundsare very common in Earth’s crust and also in seawater. Calcium is likewise the many abundant steel in the human being body, developing as calcium compound such together calcium phosphate and also calcium carbonate. These calcium compound are found in bones and make lock hard and strong. The skeleton the the mean adult contains about a kilogram the calcium. Since calcium—like barium—absorbs x-rays, bones display up white in x-ray images. Calcium is critical component the a healthy and balanced human diet. Great food sources of calcium are pictured inFigurebelow.

*

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

A:Children that don’t get enough calcium while their bones are creating may construct a deficiency an illness called rickets, in which your bones are softer than normal and become bent and stunted. Adults who don’t get sufficient calcium may construct a problem called osteoporosis, in i beg your pardon the bones lose calcium and also become weak and also brittle. People with osteoporosis room at high risk of bone fractures.

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

*

Summary

· aspects in team 2 that the regular table are referred to as alkaline earth metals. They space silvery or gray incolor. They are also reasonably soft and also low in density.

· Alkaline earth metals are really reactive due to the fact that they readily offer up their two valence electron to accomplish a complete outerenergy level, i m sorry is the many stable plan of electrons. Reactivity boosts from the peak to the bottom that the group.

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

Explore More

At the adhering to URL, observe how four different alkaline planet metals reaction withwater. After ~ you watch the video, answer 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 most to the very least reactive with water.

2. What describes the differences in reactivity?

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

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

Review

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

2. Why room alkaline planet metals very reactive?

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

Noble Gases

Characteristics of group 18 the the periodic table.

· identify the noblegases.

· perform properties that noblegases.

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

*

Okay, helium balloons are light, however they’re not that light! This fanciful photo serves to make the point 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 team 18 of the periodic table. Together you deserve to see in the periodic table inFigurebelow, noble gases include 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 are gases at roomtemperature. Radon, in ~ the bottom of the group, is radioactive, so the constantly decays come otherelements. For an excellent overview of the noble gases, clock the video at this URL:

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

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

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

*

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

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

Chemical nature of Noble Gases

Noble gases space the least reactive the all well-known elements. That’s because with eight valenceelectrons, your outer energy levels room full. The only exemption is helium, which has just two electrons. However helium additionally has a complete outerenergy level, because its only power level (energy level 1) have the right to hold a best of 2 electrons. A full outer power level is the many stable arrangement of electrons. Together a result, noble gases can not become much more stable by reaction with various other elements and gaining or losing valence electrons. Therefore, noble gases space rarely affiliated inchemical reactionsand nearly never formcompoundswith other elements.

Noble Gases and also theOctet Rule

Because the noble gases room the least reactive of every elements, your eight valence electrons are provided as the typical for nonreactivity and to define how other aspects interact. This is stated as the octet (“group the eight”) rule. According to this rule,atomsreact to formcompoundsthat permit them to have actually a team of eight valence electrons choose the noble gases. For example, salt (with one valence electron) reacts with chlorine (with seven valence electrons) to type the steady compound sodium chloride (table salt). In this reaction, sodium donates an electron and chlorine accepts it, giving each facet an octet of valence electrons.

Some provides of Noble Gases

Did you ever before get helium balloons like those in the opening picture? unlike a balloon filled v air, a balloon filled v helium needs to it is in weighted under so the won’t float away — although you don’t have to use one elephant!.

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

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

Early incandescent irradiate bulbs, favor the one pictured in theFigurebelow, didn’t last an extremely long. The filaments quickly shed out. Return air to be pumped out of the bulb, that wasn’t a complete vacuum. Oxygen in the little amount of air remaining inside the light pear reacted with the metal filament. This corroded the filament and caused dark store on the glass. Pour it until it is full a light bulb v argon gas avoids these problems. That’s why modern light bulbs are filled with argon.

Q:How walk argon prevent the troubles of at an early stage light bulbs?

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

*

Noble gases are also used to to fill the glass tubes of lighted indicators like the one in theFigurebelow. Back noble gases space chemically nonreactive, their electrons have the right to be energized by sending anelectric currentthrough them. When this happens, the electrons jump to a higherenergy level. When the electrons go back to their original energy level, they offer off power as light. Various noble gases give off light of different colors. Neon gives off reddish-orange light, like the word “Open” in the authorize below. Krypton offers off violet light and xenon offers off blue light.

*

Summary

· Noble gases space nonreactive, nonmetallic aspects in team 18 that the regular table.

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

· Theoctet rulestates thatatomsreact to form compounds that allow them to have actually eight valence electrons prefer the noble gases, which are the least reactive elements.

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

Explore More

Watch the video clip about noble gases in ~ the adhering to URL, and also then prize the concerns below.

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

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

2. Compare the thickness of these noble gases to the density of air.

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

Review

1. What space noble gases?

2. Explain why noble gases are almost totally nonreactive.

See more: List Of Things That Are Hot With H / Dictionary / Categories Game

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

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