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Hydrogen and also Alkali Metals

Characteristics of group 1 of the regular table.

You are watching: Give the number of valence electrons for alkali metals.

· determine theelementsin group 1 the the routine table.

· define why group 1elementsare very reactive.

· List other properties that alkalimetals.


You more than likely think ofwateras a problem that have the right to put the end fires. Yet someelementsare for this reason reactive that they burn in water. In fact, they basically explode in water. That’s what is continue in the picture 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 you will find out.

The very first Group

Sodium (Na) is an facet in group 1 of the periodic table the the elements. This team (column) the the table is displayed below. It consists of the nonmetal hydrogen (H) and also sixmetalsthat room calledalkali metals. Facets in the same group of the regular table have the same variety of valenceelectrons. These are the electrons in your outerenergy levelthat have the right to be connected in chemistry reactions. Valence electrons determine countless of the nature of an element, so elements in the same team have comparable properties. All the elements in group 1 have just one valence electron. This renders them very reactive.

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

A:With just one valence electron, team 1 elements are “eager” to lose that electron. Act so allows them to attain a complete outerenergy leveland preferably stability.


Reactivity of group 1 Elements

Hydrogen is a an extremely reactive gas, and also the alkalimetalsare even much more reactive. In fact, they room the many reactive metals and, along with the elements in group 17, are the most reactive of every elements. The reactivity that alkali metals rises from the top to the bottom that the group, therefore 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 discovered in nature only in combination with other elements. They often integrate with team 17 elements, i m sorry are very “eager” to gain an electron. At the URL below, you deserve to watch a video that mirrors just exactly how reactive the alkali metals are.

Other properties of Alkali Metals

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

· Alkali steels are allsolidsat roomtemperature.

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

· Alkali metals are relatively soft. Part are also soft enough to cut with a knife, prefer the sodium pictured in theFigurebelow.


A Closer Look

Although all team 1 aspects share specific properties, such as being really reactive, they room not alike in every way. Three different group 1 elements are explained in much more detail listed below (Figuresbelow,below, andbelow). Notice the methods in i m sorry they different from one another.


Hydrogen has actually the smallest, lightest atoms of all elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic however highly flammable. Hydrogen gas exists mostly as diatomic (“two-atom”) molecule (H2), as displayed in the diagram on the right. Hydrogen is the many abundant facet in the universe and the third most abundant facet on Earth, emerging mainly in compounds such together water.

Q:Why do you think hydrogen gas usually exists as diatomic molecules?

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


Potassium is a soft, silvery metal that ignites explosively in water. It easily loses that is one valence electron to type positive potassium ions (K+), i beg your pardon are needed by all living cells. Potassium is so necessary for plants that it is discovered in almost all fertilizers, choose the one shown here. Potassium is plentiful in Earth’s crust in mineral such together feldspar.


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

Q:Francium decays too quickly to formcompoundswith various other elements. Which facets to friend think it would bond through if that could?

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


· team 1 that the periodic table has hydrogen and also the alkali metals.

· since they have just one valence electron, group 1 aspects are an extremely reactive. Together a result, lock are found in nature just in combination with various other elements.

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

· indigenous the top to the bottom of team 1, the facets have heavier, an ext reactiveatoms.

Explore More

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

From the height to the bottom of team 1, properties 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. Describe why team 1 aspects often formcompoundswith aspects in team 17.

4. Compare and also contrast hydrogen and also francium.

Alkaline earth Metals

Characteristics of group 2 of the regular table.

· identify alkaline Earthmetals.

· list properties the alkaline Earthmetals.

· define why alkaline Earthmetalsare an extremely reactive.


Sparklers favor the one this girl is holding make festive additions to many celebrations. You might use castle yourself. Yet watch out if you do since their flames are really hot! The glowing white flames are created when magnesium burns. Magnesium is a light- weight steel that burns at a an extremely hightemperature. Other offers of magnesium include flash photography, flares, and fireworks. Magnesium is a steel in team 2 that the routine table, i m sorry you will certainly read around in this concept.  

The 2nd Group

Barium (Ba) is one of sixelementsin group 2 that the periodic table, which is presented below. Aspects in this group are calledalkaline earth metals. These metals are silver or gray incolor. They are fairly soft and also low in density, although no as soft and lightweight together alkali metals. You have the right to watch a brief video introduction come the alkaline planet metals at this URL:


Reactivity that Alkaline earth Metals

All alkaline earth metals have comparable properties because they all have two valenceelectrons. Lock readily give up their 2 valence electron to achieve a full outerenergy level, i m sorry is the most stable plan of electrons. As a result, castle are an extremely reactive, return not quite as reactive as the alkali metals in group 1. For example, alkaline earth metals will certainly react through coldwater, but not explosively together alkali metals do. Since of their reactivity, alkaline planet metals never exist as puresubstancesin nature. Instead, they are always found an unified with otherelements.

The reactivity of alkaline earth metals increases from the height to the bottom the the group. That’s because theatomsget bigger from the top to the bottom, therefore the valenceelectronsare farther from the nucleus. When valence electrons room farther indigenous the nucleus, they space attracted less strongly by the cell nucleus and an ext easily removed from the atom. This makes the atom much more reactive.

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

A:It takes an ext energy to remove two valenceelectronsfrom one atom 보다 one valence electron. This provides alkaline planet metals v their 2 valence electrons less reactive 보다 alkali steels with your one valence electron.

Examples of Alkaline planet Metals

For a better understanding the alkaline planet metals, let’s take it a closer look at two of them: calcium (Ca) and also strontium (Sr). Calcium is a soft, gray, nontoxic alkaline earth metal. Although pure calcium doesn’t exist in nature, calciumcompoundsare very common in Earth’s crust and also in seawater. Calcium is additionally the most abundant steel in the human body, developing as calcium compounds such together calcium phosphate and also calcium carbonate. These calcium compounds are uncovered in bones and make lock hard and also strong. The skeleton of the typical adult contains about a kilogram the calcium. Due to the fact that calcium—like barium—absorbs x-rays, bones present up white in x-ray images. Calcium is critical component the a healthy and balanced human diet. Great food resources of calcium space pictured inFigurebelow.


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

A:Children who don’t get sufficient calcium while their bones are developing may build a deficiency disease called rickets, in which your bones room softer 보다 normal and also become bent and also stunted. Adults that don’t get enough calcium may construct a condition called osteoporosis, in i m sorry the bones lose calcium and become weak and also brittle. World with osteoporosis room at high risk of bone fractures.

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



· elements in group 2 of the periodic table are referred to as alkaline earth metals. They space silvery or gray incolor. They space also fairly soft and low in density.

· Alkaline planet metals are an extremely reactive since they readily offer up their two valence electron to accomplish a full outerenergy level, i beg your pardon is the many stable arrangement of electrons. Reactivity rises from the top to the bottom the the group.

· examples of alkaline earth metals include calcium, i beg your pardon is needed for solid bones, and strontium, i beg your pardon is supplied for making cement and other products.

Explore More

At the complying with URL, observe exactly how four various alkaline earth metals reaction withwater. After ~ you watch the video, price the questions below.

1. Watch the reactions in the video, and then location the alkaline planet metals from many to the very least reactive through water.

2. What describes the differences in reactivity?

3. Suspect the reactivity of beryllium through water. Wherein would that fit in her ranking?

4. Whatsubstancesare developed in each reaction the you observed in the video?


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

2. Why space alkaline planet metals really reactive?

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

Noble Gases

Characteristics of group 18 that the routine table.

· determine the noblegases.

· perform properties that noblegases.

· define the nonreactivity of noblegasesand exactly how it is related to theoctet rule.


Okay, helium balloons room light, yet they’re no that light! This fanciful snapshot serves to make the suggest that helium is just one of the lightestelements. Helium belongs to a team of aspects called the noble gases.

What room Noble Gases?

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

· to learn just how the noble gases were discovered, walk to this URL:

· come explore details noble gases, click their symbols in the routine table at this URL:


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

A:The number of valenceelectronsstarts at one for aspects in team 1. It then increases by one from left to right across each period (row) the the regular table for groups 1–2 and also 13–18. Therefore, noble gases have actually eight valence electrons.

Chemical nature of Noble Gases

Noble gases room the the very least reactive that all known elements. That’s due to the fact that with eight valenceelectrons, your outer power levels room full. The only exemption is helium, which has just 2 electrons. However helium likewise has a complete outerenergy level, since its only power level (energy level 1) can hold a best of 2 electrons. A complete outer energy level is the most stable arrangement of electrons. As 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 are rarely connected inchemical reactionsand nearly never formcompoundswith various other elements.

Noble Gases and also theOctet Rule

Because the noble gases room the least reactive of all elements, their eight valence electrons are provided as the traditional for nonreactivity and to explain how other facets interact. This is stated as the octet (“group that eight”) rule. Follow to this rule,atomsreact to formcompoundsthat permit them to have a group of eight valence electrons choose the noble gases. Because that example, salt (with one valence electron) reacts through chlorine (with seven valence electrons) to kind the stable compound sodium chloride (table salt). In this reaction, salt donates one electron and chlorine accepts it, giving each facet an octet of valence electrons.

Some uses of Noble Gases

Did you ever before get helium balloons favor those in the opened picture? unequal a balloon filled v air, a balloon filled v helium needs to be weighted under so that won’t float far — although girlfriend don’t need to use an elephant!.

Q:Why does a helium balloon float far if it’s no weighted down?

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

Early incandescent light bulbs, like the one pictured in theFigurebelow, didn’t last very long. The filaments quickly shed out. Return air was pumped the end of the bulb, the wasn’t a complete vacuum. Oxygen in the small amount the air continuing to be inside the light pear reacted through the steel filament. This corroded the filament and caused dark shop on the glass. Pour it until it is full a light bulb through argon gas stays clear of these problems. That’s why contemporary light bulbs space filled with argon.

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

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


Noble gases are likewise used to fill the glass pipe of lighted indications like the one in theFigurebelow. Back noble gases room chemically nonreactive, their electrons deserve to be energized by sending anelectric currentthrough them. Once this happens, the electrons run to a higherenergy level. Once the electrons return to their original power level, they offer off energy as light. Various noble gases give off light of different colors. Neon offers off reddish-orange light, choose the indigenous “Open” in the sign below. Krypton gives off violet light and xenon provides off blue light.



· Noble gases room nonreactive, nonmetallic elements in group 18 the the periodic 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 many stable arrangement of electrons, for this reason noble gases seldom react with other elements and formcompounds.

· Theoctet rulestates thatatomsreact to type compounds that enable them to have eight valence electrons prefer the noble gases, which are the the very least reactive elements.

· Noble gases are offered for balloons, irradiate bulbs, and also lighted signs.

Explore More

Watch the video clip about noble gases at the adhering to URL, and then answer the inquiries below.

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

2. Compare the density of these noble gases come the density of air.

3. Define how the mass of noble gases alters from the height to the bottom of group 18.


1. What room noble gases?

2. Describe why noble gases space almost fully nonreactive.

See more: Convert 38 Degrees Celsius To Fahrenheit Conversion, Celsius To Fahrenheit Conversion

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

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