assignments --> unit 3 part 3 --> hydrogen and also alkali metals
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Hydrogen and also Alkali Metals
Characteristics of group 1 the the regular table.
You are watching: How many valence electrons do alkaline earth metals have
· recognize theelementsin group 1 of the routine table.
· explain why group 1elementsare very reactive.
· List other properties the alkalimetals.
You more than likely think ofwateras a problem that can put out fires. Yet someelementsare for this reason reactive that they burn in water. In fact, they basically explode in water. That’s what is keep going in the photo above. Around 3 pounds of sodium were included to water, and also the result was this explosive reaction. Why is salt such a reactive element? In this lesson friend will discover out.
The first Group
Sodium (Na) is an facet in group 1 the the periodic table that the elements. This team (column) the the table is shown below. It has the nonmetal hydrogen (H) and sixmetalsthat are calledalkali metals. Elements in the same team of the routine table have actually the same variety of valenceelectrons. These space the electron in your outerenergy levelthat deserve to be connected in chemistry reactions. Valence electrons determine many of the properties of one element, so aspects in the same group have comparable properties. Every the facets in group 1 have actually just one valence electron. This renders them really reactive.
Q:Why does having actually just one valence electron make team 1 elements very reactive?
A:With simply one valence electron, team 1 aspects are “eager” to shed that electron. Law so allows them to accomplish a complete outerenergy leveland best stability.
Reactivity of team 1 Elements
Hydrogen is a really reactive gas, and the alkalimetalsare even more reactive. In fact, they room the many reactive metals and, in addition to the facets in team 17, room the many reactive of all elements. The reactivity that alkali metals increases from the optimal to the bottom the the group, so lithium (Li) is the the very least reactive alkali metal and also francium (Fr) is the most reactive. Due to the fact that alkali metals are therefore reactive, they are uncovered in nature just in mix with other elements. Lock often combine with team 17 elements, i beg your pardon are really “eager” to acquire an electron. At the URL below, you can watch a video that mirrors just just how reactive the alkali steels are.
Other properties of Alkali Metals
Besides being really reactive, alkali metals share a variety of other properties.
· Alkali metals are allsolidsat roomtemperature.
· Alkali steels are low in density, and also some of lock float onwater.
· Alkali steels are fairly soft. Some are even soft sufficient to cut with a knife, like the salt pictured in theFigurebelow.
A Closer Look
Although all team 1 facets share specific properties, such as being very reactive, they space not alike in every way. Three various group 1 aspects are defined in an ext detail listed below (Figuresbelow,below, andbelow). An alert the methods in i beg your pardon they different from one another.
Hydrogen has actually the smallest, lightest atom of all elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic yet highly flammable. Hydrogen gas exists mostly as diatomic (“two-atom”) molecule (H2), as presented in the chart on the right. Hydrogen is the most abundant aspect in the universe and also the third most abundant aspect on Earth, developing mainly in compounds such as water.
Q:Why perform you think hydrogen gas typically exists together diatomic molecules?
A:Each hydrogen atom has actually just one electron. As soon as two hydrogenatomsbond together, castle share a pair ofelectrons. The mutual electrons fill their onlyenergy level, providing them the many stable plan of electrons.
Potassium is a soft, silvery metal that ignites explosively in water. It quickly loses the one valence electron to form positive potassium ion (K+), i beg your pardon are essential by every living cells. Potassium is so essential for plants the it is discovered in virtually all fertilizers, choose the one presented here. Potassium is plentiful in Earth’s tardy in minerals such together feldspar.
Francium has actually one of the largest, heaviest atom of every elements. The one valence electron is far removed native the nucleus, as you can see in the atomic model on the right, so it is quickly removed native the atom. Francium is radioactive and also quickly decays to form other aspects such together radium. This is why francium is exceptionally rare in nature. Less than an ounce of francium is present on planet at any type of given time.
Q:Francium decays too conveniently to formcompoundswith other elements. Which facets to you think it would certainly bond through if that could?
A:With one valence electron, francium would certainly bond through a halogen element in group 17, which has actually seven valenceelectronsand needs one an ext to to fill its outer power level. Facets in team 17 encompass fluorine and chlorine.
· team 1 that the routine table has hydrogen and also the alkali metals.
· due to the fact that they have just one valence electron, team 1 aspects are very reactive. As a result, lock are discovered in nature only in combination with various other elements.
· Alkali metals are allsolidsat roomtemperature. Castle are relatively soft and also low in density.
· native the height to the bottom of team 1, the elements have heavier, much more reactiveatoms.
At the following URL, click “Group 1 data and also graphs.” usage the data in the team 1 table to fill in the blanks listed below with eitherincreasesordecreases.
From the optimal to the bottom of team 1, nature of the alkali metals change as follows:
1. Melting suggest __________.
2. Boiling suggest __________.
3. Thickness __________.
4. Atom radius __________.
5. Number of electrons __________.
1. What room alkali metals?
2. Why is hydrogen, a nonmetal, put in the same group as the alkali metals?
3. Explain why group 1 facets often formcompoundswith aspects in group 17.
4. Compare and contrast hydrogen and also francium.
Alkaline earth Metals
Characteristics of team 2 of the regular table.
· identify alkaline Earthmetals.
· list properties that alkaline Earthmetals.
· describe why alkaline Earthmetalsare an extremely reactive.
Sparklers choose the one this girl is holding do festive enhancements to plenty of celebrations. You might use lock yourself. Yet watch out if you do due to the fact that their flames are really hot! The shining white flames are produced when magnesium burns. Magnesium is a light- weight metal that burns in ~ a really hightemperature. Other supplies of magnesium incorporate flash photography, flares, and also fireworks. Magnesium is a metal in group 2 that the routine table, i beg your pardon you will certainly read about in this concept.
The second Group
Barium (Ba) is among sixelementsin team 2 the the regular table, which is presented below. Elements in this team are calledalkaline earth metals. These metals are silver- or gray incolor. They are relatively soft and also low in density, although no as soft and lightweight together alkali metals. You can watch a brief video clip introduction come the alkaline planet metals in ~ this URL:http://www.youtube.com/watch?v=DFQPnHkQlZM.
Reactivity that Alkaline earth Metals
All alkaline earth metals have similar properties due to the fact that they all have actually two valenceelectrons. Castle readily give up their 2 valence electron to achieve a complete outerenergy level, i beg your pardon is the many stable setup of electrons. Together a result, castle are an extremely reactive, back not rather as reactive together the alkali metals in team 1. Because that example, alkaline planet metals will certainly react v coldwater, however not explosively together alkali steels do. Since of their reactivity, alkaline planet metals never exist as puresubstancesin nature. Instead, lock are constantly found an unified with otherelements.
The reactivity of alkaline earth metals boosts from the height to the bottom of the group. That’s due to the fact that theatomsget bigger indigenous the height to the bottom, therefore the valenceelectronsare farther from the nucleus. When valence electrons are farther native the nucleus, they room attracted less strongly through the cell nucleus and more easily gotten rid of 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 보다 one valence electron. This renders alkaline planet metals through their two valence electrons much less reactive 보다 alkali metals with your one valence electron.
Examples of Alkaline planet Metals
For a much better understanding of alkaline planet metals, let’s take a closer look 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 in seawater. Calcium is also the most abundant steel in the person body, developing as calcium compounds such as calcium phosphate and also calcium carbonate. This calcium compounds are uncovered in bones and also make them hard and also strong. The skeleton the the average adult contains around a kilogram of calcium. Due to the fact that calcium—like barium—absorbs x-rays, bones show up white in x-ray images. Calcium is an essential component that a healthy and balanced human diet. Great food sources of calcium are pictured inFigurebelow.
Q:What health troubles might result from a diet short in calcium?
A:Children that don’t get sufficient calcium while their bones are developing may develop a deficiency an illness called rickets, in which their bones room softer than normal and also become bent and also stunted. Adults that 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 room at high hazard of bone fractures.
Strontium is a silver-colored alkaline earth metal that is also 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, prefer the one pictured in theFigurebelow, the link strontium chloride reduces tooth sensitivity.
· elements in group 2 of the routine table are referred to as alkaline earth metals. They space silvery or gray incolor. They are also fairly soft and low in density.
· Alkaline planet metals are an extremely reactive due to the fact that they readily offer up their two valence electrons to accomplish a full outerenergy level, i m sorry is the many stable setup of electrons. Reactivity increases from the height to the bottom the the group.
· examples of alkaline earth metals incorporate calcium, i beg your pardon is needed for strong bones, and strontium, i m sorry is used for making cement and also other products.
At the adhering to URL, observe just how four various alkaline planet metals reaction withwater. ~ you watch the video, answer the questions below.
1. Watch the reaction in the video, and then rank the alkaline earth metals from many to least reactive through water.
2. What describes the distinctions in reactivity?
3. Suspect the reactivity the beryllium with water. Whereby would that fit in your ranking?
4. Whatsubstancesare developed in every reaction the you observed in the video?
1. What are alkaline planet metals? What are their physics properties?
2. Why space alkaline planet metals very reactive?
3. Compare and contrast the reactivity that beryllium (Be) and also barium (Ba).
Characteristics of group 18 of the routine table.
· identify the noblegases.
· list properties the noblegases.
· describe the nonreactivity of noblegasesand how it is regarded theoctet rule.
Okay, helium balloons are light, yet they’re not that light! This fanciful snapshot serves to make the suggest that helium is just one of the lightestelements. Helium belongs come a group of elements called the noble gases.
What room Noble Gases?
Noble gasesare nonreactive, nonmetallicelementsin team 18 that the regular table. Together you deserve to see in the regular table inFigurebelow, noble gases incorporate helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Every noble gases are colorless and odorless. They likewise have lowboilingpoints, explaining why they space gases at roomtemperature. Radon, at the bottom the the group, is radioactive, so the constantly decays come otherelements. For fantastic overview of the noble gases, clock the video clip at this URL:
· come learn how the noble gases to be discovered, go to this URL:http://www.youtube.com/watch?v=ceQMs30D16E.
· come explore certain noble gases, click on their signs in the routine table in ~ this URL:http://www.ptable.com/.
Q:Based ~ above their place in the periodic table (Figureabove), how numerous valenceelectronsdo you think noble gases have?
A:The variety of valenceelectronsstarts at one for facets in team 1. That then rises by one native left come right across each period (row) of the regular table for teams 1–2 and 13–18. Therefore, noble gases have eight valence electrons.
Chemical properties of Noble Gases
Noble gases are the least reactive that all well-known elements. That’s due to the fact that with eight valenceelectrons, your outer energy levels room full. The only exception is helium, which has just 2 electrons. However helium also has a complete outerenergy level, since its only power level (energy level 1) have the right to hold a maximum of 2 electrons. A complete outer power level is the many stable setup of electrons. As a result, noble gases can not become an ext stable by reacting with various other elements and also gaining or losing valence electrons. Therefore, noble gases room rarely affiliated inchemical reactionsand nearly never formcompoundswith other elements.
Noble Gases and also theOctet Rule
Because the noble gases room the the very least reactive of all elements, your eight valence electron are offered as the standard for nonreactivity and also to describe how other aspects interact. This is declared as the octet (“group of eight”) rule. According to this rule,atomsreact come formcompoundsthat permit them to have a group of eight valence electrons favor the noble gases. For example, salt (with one valence electron) reacts with chlorine (with 7 valence electrons) to type the secure compound sodium chloride (table salt). In this reaction, sodium donates an electron and also chlorine accepts it, offering each aspect an octet that 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 with helium demands to be weighted under so it won’t float far — although girlfriend don’t have to use an elephant!.
Q:Why walk a helium balloon float far 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. Together a result, helium is lighter 보다 air, explaining why a helium balloon floats up right into the air unless weighted down.
Early incandescent irradiate bulbs, choose the one pictured in theFigurebelow, didn’t last very long. The filaments quickly melted out. Return air was pumped out of the bulb, that wasn’t a complete vacuum. Oxygen in the little amount of air continuing to be inside the light bulb reacted v the metal filament. This corroded the filament and also caused dark deposits on the glass. Filling a light bulb v argon gas stays clear of these problems. That’s why modern light bulbs room filled through argon.
Q:How walk argon stop the troubles of beforehand 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 keeps the glass blub complimentary of deposits.
Noble gases are also used to fill the glass tubes of lighted indicators like the one in theFigurebelow. Although noble gases room chemically nonreactive, their electrons have the right to be energized by sending anelectric currentthrough them. As soon as 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. Different noble gases provide off irradiate of various colors. Neon provides off reddish-orange light, like the word “Open” in the sign below. Krypton offers off violet light and also xenon offers off blue light.
· Noble gases room nonreactive, nonmetallic facets in group 18 the the routine table.
· Noble gases room the the very least reactive of all elements. That’s since they have eight valence electrons, which fill their outerenergy level. This is the most stable setup of electrons, therefore noble gases hardly ever react with other elements and formcompounds.
· Theoctet rulestates thatatomsreact to type compounds that permit them to have eight valence electrons favor the noble gases, which room the the very least reactive elements.
· Noble gases are used for balloons, irradiate bulbs, and also lighted signs.
Watch the video clip about noble gases at the complying with URL, and also then price the concerns below.
1. Compare and contrast the reactivity of the facets helium, neon, argon, krypton, and also xenon.
2. To compare the density of these noble gases come the thickness of air.
3. Describe how the mass of noble gases alters from the height to the bottom of team 18.
1. What room noble gases?
2. Describe why noble gases space almost fully nonreactive.
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3. What is the octet rule? just how is it related to noble gases?
4. Hydrogen (H) atoms have one electron and exist together diatomic (“two-atom”) molecule (H2). Helium atoms have two electrons and also exist only as single helium atoms. Explain why hydrogen and also helium different in this way.