assignments --> unit 3 part 3 --> hydrogen and also alkali metals
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Hydrogen and Alkali Metals
Characteristics of team 1 that the routine table.
You are watching: The alkaline earth metals have how many valence electrons?
· identify theelementsin team 1 the the periodic table.
· describe why group 1elementsare very reactive.
· List other properties that alkalimetals.
You more than likely think ofwateras a substance that can put out fires. Yet someelementsare therefore reactive that they burn in water. In fact, they basically explode in water. That’s what is continue in the picture above. About 3 pounds of salt were included to water, and also the result was this explosive reaction. Why is sodium such a reactive element? In this lesson girlfriend will find out.
The first Group
Sodium (Na) is an facet in team 1 of the regular table the the elements. This group (column) that the table is shown below. It has the nonmetal hydrogen (H) and also sixmetalsthat room calledalkali metals. Elements in the same team of the periodic table have actually the same variety of valenceelectrons. These space the electrons in your outerenergy levelthat deserve to be involved in chemical reactions. Valence electron determine many of the nature of one element, so facets in the same team have similar properties. Every the elements in group 1 have just one valence electron. This provides them an extremely reactive.
Q:Why does having actually just one valence electron make group 1 elements really reactive?
A:With simply one valence electron, team 1 aspects are “eager” to shed that electron. Law so enables them to attain a complete outerenergy leveland maximum stability.
Reactivity of team 1 Elements
Hydrogen is a very reactive gas, and also the alkalimetalsare even much more reactive. In fact, they are the most reactive steels and, together with the elements in group 17, room the many reactive of every elements. The reactivity that alkali metals increases from the optimal to the bottom that the group, therefore lithium (Li) is the least reactive alkali metal and also francium (Fr) is the most reactive. Due to the fact that alkali steels are so reactive, castle are discovered in nature just in combination with various other elements. Lock often combine with group 17 elements, which are an extremely “eager” to acquire an electron. In ~ the URL below, you have the right to watch a video clip that shows just exactly how reactive the alkali steels are.
Other properties of Alkali Metals
Besides being very reactive, alkali metals share a number of other properties.
· Alkali metals are allsolidsat roomtemperature.
· Alkali steels are low in density, and some of them float onwater.
· Alkali metals are fairly soft. Part are even soft enough to cut with a knife, favor the salt pictured in theFigurebelow.
A Closer Look
Although all team 1 aspects share particular properties, such as being really reactive, they are not alike in every way. Three various group 1 elements are explained in an ext detail below (Figuresbelow,below, andbelow). An alert the ways in i m sorry they different from one another.
Hydrogen has the smallest, lightest atom of every elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic but highly flammable. Hydrogen gas exists mainly as diatomic (“two-atom”) molecule (H2), as shown 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 compound such as water.
Q:Why carry out you think hydrogen gas generally exists together diatomic molecules?
A:Each hydrogen atom has just one electron. Once two hydrogenatomsbond together, lock share a pair ofelectrons. The common electrons fill their onlyenergy level, providing them the many stable arrangement 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 ions (K+), which are essential by every living cells. Potassium is so important for plants that it is found in almost all fertilizers, like the one displayed here. Potassium is plentiful in Earth’s crust in mineral such together feldspar.
Francium has one that the largest, heaviest atom of every elements. That one valence electron is far removed native the nucleus, together you deserve to see in the atomic model on the right, so the is quickly removed indigenous the atom. Francium is radioactive and quickly decays to type other elements such together radium. This is why francium is incredibly rare in nature. Less than an oz of francium is existing on planet at any given time.
Q:Francium decays too conveniently to formcompoundswith various other elements. Which aspects to girlfriend think it would certainly bond with if it could?
A:With one valence electron, francium would certainly bond with a halogen element in team 17, which has actually seven valenceelectronsand demands one much more to fill its outer energy level. Aspects in group 17 include fluorine and also chlorine.
· group 1 the the periodic table consists of hydrogen and the alkali metals.
· because they have just one valence electron, team 1 aspects are very reactive. Together a result, lock are discovered in nature just in mix with various other elements.
· Alkali steels are allsolidsat roomtemperature. They are fairly soft and low in density.
· native the optimal to the bottom of team 1, the facets have heavier, an ext reactiveatoms.
At the complying with URL, click “Group 1 data and graphs.” use the data in the group 1 table to to fill in the blanks listed below with eitherincreasesordecreases.
From the height to the bottom of group 1, properties of the alkali metals change as follows:
1. Melting point __________.
2. Boiling allude __________.
3. Density __________.
4. Atomic radius __________.
5. Number of electrons __________.
1. What are alkali metals?
2. Why is hydrogen, a nonmetal, placed in the same group as the alkali metals?
3. Explain why group 1 elements often formcompoundswith aspects in group 17.
4. Compare and also contrast hydrogen and francium.
Alkaline earth Metals
Characteristics of team 2 the the regular table.
· recognize alkaline Earthmetals.
· list properties that alkaline Earthmetals.
· describe why alkaline Earthmetalsare very reactive.
Sparklers favor the one this girl is holding make festive enhancements to numerous celebrations. You may use castle yourself. But watch the end if friend do because their flames space really hot! The bright white flames are produced when magnesium burns. Magnesium is a light- weight steel that burns at a very hightemperature. Other uses of magnesium include flash photography, flares, and fireworks. Magnesium is a steel in team 2 the the routine table, i beg your pardon you will read about in this concept.
The second Group
Barium (Ba) is among sixelementsin group 2 that the periodic table, i m sorry is presented below. Aspects in this group are calledalkaline planet metals. These steels are silver- or gray incolor. Lock are relatively soft and also low in density, although not as soft and lightweight as alkali metals. You can watch a brief video clip introduction to the alkaline planet metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.
Reactivity that Alkaline earth Metals
All alkaline earth metals have comparable properties due to the fact that they all have two valenceelectrons. Castle readily offer up their two valence electron to accomplish a complete outerenergy level, i beg your pardon is the most stable arrangement of electrons. As a result, lock are really reactive, although not rather as reactive as the alkali steels in group 1. Because that example, alkaline planet metals will certainly react v coldwater, yet not explosively as alkali steels do. Due to the fact that of their reactivity, alkaline planet metals never exist as puresubstancesin nature. Instead, castle are always found combined with otherelements.
The reactivity that alkaline earth metals increases from the top to the bottom that the group. That’s due to the fact that theatomsget bigger from the height to the bottom, therefore the valenceelectronsare farther from the nucleus. When valence electrons space farther indigenous the nucleus, they room attracted much less strongly by the cell nucleus and much more easily eliminated from the atom. This renders the atom an ext reactive.
Q:Alkali metals have just one valence electron. Why are alkaline earth metals much less reactive than alkali metals?
A:It takes an ext energy to eliminate two valenceelectronsfrom one atom 보다 one valence electron. This renders alkaline planet metals v their 2 valence electrons less reactive 보다 alkali metals with their one valence electron.
Examples the Alkaline earth Metals
For a much better understanding of alkaline earth metals, let’s take it a closer watch at two of them: calcium (Ca) and strontium (Sr). Calcium is a soft, gray, nontoxic alkaline planet metal. Back pure calcium doesn’t exist in nature, calciumcompoundsare an extremely common in Earth’s crust and also in seawater. Calcium is likewise the many abundant metal in the person body, occurring as calcium compounds such together calcium phosphate and calcium carbonate. These calcium compound are discovered in bones and make them hard and strong. The skeleton of the typical adult contains around a kilogram that calcium. Since calcium—like barium—absorbs x-rays, bones display up white in x-ray images. Calcium is an important component the a healthy human diet. An excellent food resources of calcium room pictured inFigurebelow.
Q:What health troubles might an outcome from a diet short in calcium?
A:Children who don’t get sufficient calcium while their bones are developing may construct a deficiency disease called rickets, in which your bones space softer than normal and also become bent and also stunted. Adults who don’t get sufficient calcium may develop a condition called osteoporosis, in which the bones lose calcium and also become weak and also brittle. Human being with osteoporosis room at high danger of bone fractures.
Strontium is a silver-colored alkaline planet metal the is also softer 보다 calcium. Strontiumcompoundsare rather common and have a selection 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.
· aspects in group 2 of the periodic table are referred to as alkaline planet metals. They space silvery or gray incolor. They space also reasonably soft and also low in density.
· Alkaline earth metals are really reactive because they readily offer up their two valence electrons to achieve a full outerenergy level, i beg your pardon is the most stable plan of electrons. Reactivity boosts from the optimal to the bottom the the group.
· examples of alkaline earth metals encompass calcium, i m sorry is needed for strong bones, and strontium, i beg your pardon is offered for making cement and other products.
At the complying with URL, observe just how four various alkaline earth metals reaction withwater. After ~ you clock the video, price the inquiries below.
1. Watch the reaction in the video, and then location the alkaline earth metals from many to least reactive with water.
2. What defines the distinctions in reactivity?
3. Guess the reactivity the beryllium with water. Where would that fit in your ranking?
4. Whatsubstancesare developed in each reaction that you observed in the video?
1. What room alkaline planet metals? What room their physical properties?
2. Why are alkaline planet metals an extremely reactive?
3. Compare and contrast the reactivity the beryllium (Be) and barium (Ba).
Characteristics of group 18 of the periodic table.
· identify the noblegases.
· list properties the noblegases.
· describe the nonreactivity the noblegasesand exactly how it is pertained to theoctet rule.
Okay, helium balloons room light, however they’re no that light! This fanciful picture serves to do the point that helium is just one of the lightestelements. Helium belongs come a team of elements 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 regular table inFigurebelow, noble gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and also radon (Rn). All noble gases room colorless and odorless. They additionally have lowboilingpoints, explaining why they room gases at roomtemperature. Radon, at the bottom that the group, is radioactive, so the constantly decays come otherelements. For great overview that the noble gases, clock the video clip 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 on their icons in the routine table in ~ this URL:http://www.ptable.com/.
Q:Based on their position in the periodic table (Figureabove), how numerous valenceelectronsdo girlfriend think noble gases have?
A:The variety of valenceelectronsstarts at one for aspects in team 1. The then rises by one from left come right throughout each period (row) that the regular table for teams 1–2 and also 13–18. Therefore, noble gases have eight valence electrons.
Chemical nature of Noble Gases
Noble gases space the least reactive of all recognized elements. That’s since with eight valenceelectrons, their outer power levels room full. The only exemption is helium, which has actually just 2 electrons. However helium also has a full outerenergy level, due to the fact that its only energy level (energy level 1) have the right to hold a maximum of two electrons. A full outer power level is the many stable arrangement of electrons. As a result, noble gases can not become an ext stable by reaction with other elements and also gaining or shedding valence electrons. Therefore, noble gases space rarely involved inchemical reactionsand practically never formcompoundswith various other elements.
Noble Gases and also theOctet Rule
Because the noble gases room the least reactive of every elements, their eight valence electron are provided as the standard for nonreactivity and to describe how other aspects interact. This is declared as the octet (“group that eight”) rule. Follow to this rule,atomsreact come formcompoundsthat enable them to have actually a team of eight valence electrons favor the noble gases. Because that example, sodium (with one valence electron) reacts through chlorine (with 7 valence electrons) to form the steady compound sodium chloride (table salt). In this reaction, sodium donates an electron and chlorine accepts it, offering each aspect an octet the valence electrons.
Some uses of Noble Gases
Did you ever before get helium balloons choose those in the opened picture? unlike a balloon filled v air, a balloon filled v helium demands to be weighted under so the won’t float away — although friend don’t need to use an elephant!.
Q:Why walk a helium balloon float away if it’s no weighted down?
A:Heliumatomshave just twoprotons, twoneutrons, and also two electrons, so they have less mass than any other atoms except hydrogen. As a result, helium is lighter 보다 air, explaining why a helium balloon floats up right into the air uneven weighted down.
Early incandescent light bulbs, choose the one pictured in theFigurebelow, didn’t last an extremely long. The filaments quickly shed out. Although air was pumped out of the bulb, that wasn’t a complete vacuum. Oxygen in the tiny amount that air staying inside the light bulb reacted through the steel filament. This corroded the filament and caused dark store on the glass. Filling a irradiate bulb with argon gas stays clear of these problems. That’s why contemporary light bulbs space filled with argon.
Q:How go argon stop the troubles of at an early stage light bulbs?
A:As a noble gas through eight electrons, argon doesn’t react through the metal in the filament. This protects the filament and also keeps the glass blub complimentary of deposits.
Noble gases are likewise used to fill the glass pipe of lighted indicators like the one in theFigurebelow. Return noble gases room chemically nonreactive, their electrons deserve to be energized by sending out anelectric currentthrough them. As soon as this happens, the electrons run to a higherenergy level. Once the electrons return to their original energy level, they offer off energy as light. Various noble gases give off irradiate of different colors. Neon offers off reddish-orange light, choose the indigenous “Open” in the authorize below. Krypton offers off violet light and xenon gives off blue light.
· Noble gases space nonreactive, nonmetallic facets in group 18 the the routine table.
· Noble gases space the least reactive of every elements. That’s due to the fact that they have eight valence electrons, which fill their outerenergy level. This is the most stable arrangement of electrons, therefore noble gases seldom react with other elements and also formcompounds.
· Theoctet rulestates thatatomsreact to kind 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 supplied for balloons, irradiate bulbs, and lighted signs.
Watch the video clip about noble gases at the adhering to URL, and also then prize the inquiries below.
1. Compare and contrast the reactivity the the elements helium, neon, argon, krypton, and xenon.
2. Compare the thickness of these noble gases come the density of air.
3. Describe how the mass of noble gases transforms from the height to the bottom of group 18.
1. What are noble gases?
2. Describe why noble gases room almost totally nonreactive.
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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”) molecules (H2). Helium atoms have two electrons and exist only as solitary helium atoms. Explain why hydrogen and also helium differ in this way.