assignments --> Unit 3 part 4


shift Metals

teams with metalloids


Characteristics of group 17 of the regular table.

You are watching: How many valence electrons do halogens have

· identify halogens.

· define physical and also chemical nature of halogens.

· perform some provides of halogens.


You’ve probably seen halogen lights like the people pictured here. Friend may also have halogen lamp in her home. If you do, girlfriend may have noticed the they obtain really hot and give turn off a lot of light for their size. A halogen light differs from a continuous incandescent light bulb in having a small amount the halogen gas within the bulb. The gas combines chemically through the metal in the filament, and also this expand the life that the filament. It enables the lamp to obtain hotter and give off much more light than a constant incandescent irradiate without burning the end quickly. What is halogen gas, and whichelementsare halogens? In this article, you’ll discover out.  

Meet the Halogens

Halogensare very reactive nonmetallicelementsin group 17 of the routine table. Together you have the right to see in the periodic table shown in theFigurebelow, the halogens include theelementsfluorine (F), chlorine (Cl), bromine (Br), iodine (I), and also astatine (At). All of them are fairly common on planet except because that astatine. Astatine is radioactive and also rapidly decays to other, an ext stable elements. As a result, it is just one of the the very least common facets on Earth.


Q:Based on their position in the regular table native theFigureabove, how countless valenceelectronsdo you think halogens have?

A:The variety of valenceelectronsstarts in ~ one for facets in group 1. That then increases by one native left to right across each duration (row) the the regular table for teams 1–2 and 13–18. Therefore, halogens have actually seven valence electrons.

Chemical properties of Halogens

The halogens are amongst the most reactive of every elements, return reactivity decreases from the optimal to the bottom the the halogen group. Due to the fact that all halogens have actually seven valenceelectrons, they space “eager” to gain one much more electron. Act so provides them a complete outerenergy level, i m sorry is the most stable setup of electrons. Halogens often combine with alkalimetalsin team 1 the the routine table. Alkali metals have actually just one valence electron, i m sorry they space equally “eager” come donate. Reactions entailing halogens, especially halogens close to the top of the group, may be explosive. You can see some instances in the video clip at the URL below. (Warning:Don’t shot any of this reactions at home!)


Physical nature of Halogens

The halogen group is fairly diverse. The includes facets that occur in 3 differentstates that matterat roomtemperature. Fluorine and chlorine aregases, bromine is a liquid, and iodine and astatine aresolids. Halogens likewise varyincolor, as you can see in theFigurebelow. Fluorine and chlorine are green, bromine is red, and also iodine and astatine are virtually black. Like other nonmetals, halogens cannot conduct electricity orheat. Compared with most other elements, halogens have fairly lowmeltingandboilingpoints. You can watch a lab demonstration the the melting and boiling points of halogens at this URL:http://www.youtube.com/watch?v=yP0U5rGWqdg.


Uses that Halogens

Most halogens have actually a variety of necessary uses. A couple of are described in theTablebelow.

A few Uses the Halogens




Fluorine helps stop tooth decay, so the is included to toothpaste as the compound sodium fluoride. You have the right to learn exactly how it protects teeth at this URL:http://www.animated-teeth.com/tooth_decay/t4_tooth_decay_fluoride.htm.


Chlorine is the energetic ingredient in household bleach. It clears stains native clothes. That can also be used to disinfect countertops and also other surfaces.


Bromine is provided to purifywaterin swimming pools and also hot tubs. That reacts v bacteria and other germs and also renders them harmless.


Iodine is included to alcohol and also used together an antiseptic. That reacts through germs top top cuts and wounds. Little amounts the iodine are additionally needed for an excellent health. In the U.S., iodine is included to table salt to stop iodine deficiencies. Walk the salt you usage contain iodine?

Q:Can friend relate some of these supplies of halogens come the properties of this elements?

A:The capability of halogens to kill germs and bleach clothes relates to their highly reactive nature.


· Halogens are highly reactive nonmetal facets in group 17 the the regular table.

· Halogens includesolids,liquids, andgasesat roomtemperature, and they differ incolor.

· Halogens are amongst the most reactive of every elements. They have actually seven valence electrons, so they are really “eager” to get one electron to have a full outerenergy level.

· Halogens have actually a selection of necessary uses, together as staying clear of tooth decay and killing germs.

Explore More

TheTablebelowgives themeltingandboilingpoints the halogens. Create a graph with the data, and then describe in indigenous the trends that you check out in your graph.

MeltingandBoilingPoints the Halogens


Melting allude (°C)

Boiling allude (°C)

















1. What are halogens?

2. Why space halogens very reactive?

3. Define the physics properties the halogens.

4. Why is chlorine added to swimming poolwater?

Transition Metals

Characteristics of groups 3 - 12 the the regular table.

· identify transitionmetals.

· perform properties of transitionmetals.

· describe thelanthanides and also actinides.


What do all of the objects pictured over have in common? every one of them space made completely or mainly of copper. Copper has actually an amazing selection of uses, including food preparation pots, plumbing pipes, roofing tiles, jewelry,musical instruments, and electric wires. Copper is a an excellent choice because that these and also many other objects because of that is properties. It have the right to be created into wires and flat sheets, it’s a great conductor ofheatand electricity, it’s hard and also strong, and it doesn’t corrode easily. In every these ways, copper is a typical change metal.

What room TransitionMetals?

Transition metalsare all theelementsin teams 3–12 the the periodic table. In the regular table pictured inFigurebelow, they space theelementsshaded yellow, pink, and purple. The transition metals do up around 60 percent of all known elements. In addition to copper (Cu), well known examples of transition metals encompass iron (Fe), zinc (Zn), silver (Ag), and gold (Au) (Copper (Cu) is pictured in its assorted applications in the opening image). You can explore specific transition metals with the interactive regular table in ~ this URL:http://www.ptable.com/.


Q:Transition metals have been referred to as the most common of every metals. What execute you think this means?

A:Unlike some other metals, transition metals have actually the nature that specify the steels class. Castle are fantastic conductors of electricity, because that example, and they additionally have luster, malleability, and ductility. You have the right to read an ext about these properties of transition metals below.

Properties of transition Metals

Transition metals are premium conductors ofheatas well as electricity. They are malleable, which way they can be shaped into sheets, and also ductile, which way they can be shaped into wires. They have actually highmeltingandboilingpoints, and all aresolidsat roomtemperature, other than for mercury (Hg), i m sorry is a liquid. Transition metals are also high in thickness and very hard. Most of them space white or silvery incolor, and they are generally lustrous, or shiny. Thecompoundsthat transition metals kind with otherelementsare often very colorful. You have the right to see several examples in theFigurebelow.


Some nature of change metals set them personal from various other metals. Contrasted with the alkali metals in team 1 and also the alkaline earth metals in team 2, the shift metals room much much less reactive. They don’t react quickly withwateror oxygen, which explains why lock resistcorrosion.

Other properties of the shift metals space unique. They are the only aspects that may useelectronsin the beside highest—as well as the highest—energy levelas valence electrons. Valence electrons are the electrons that type bonds with other facets incompoundsand that usually determine the nature of elements. Transition metals space unusual in having very comparable properties also with different numbers the valence electrons. The shift metals likewise include the only aspects that produce a magnetic field. Three of them have actually this property: stole (Fe), cobalt (Co), and nickel (Ni).

Q:How is the variety of valenceelectronstypically concerned the properties of elements?

A:The variety of valenceelectronsusually determines how reactive facets are and also the means in which they react with various other elements.

Those elements Down Under

Transition metals incorporate the aspects that room most regularly placed listed below the regular table (the pink- and purple-shaded facets in theFigureabove). Those that follow lanthanum (La) are called lanthanides. They room all reasonably reactive for change metals. Those the follow actinium (Ac) are called actinides. They space all radioactive. This means that they are unstable, for this reason they degeneration into different, much more stable elements. Plenty of of the actinides do not take place in nature yet are make inlaboratories.


· change metals space all the aspects in teams 3–12 that the routine table. More than half of all facets are shift metals.

· transition metals are usual metals, v properties such as a superior capacity to conduct electrical power andheat. They additionally have the metallic nature of luster, malleability, and ductility. In addition, shift metals have highmeltingandboilingpoints and high density.

· Thelanthanides and actinidesare the change metals that are usually placed below the main part of the periodic table. Lanthanides are fairly reactive for change metals, and actinides are radioactive.

Explore More

At the complying with URL, click on any type of two the the transition metals and also read around their properties,atomic structure, discovery, and uses. Then create a i comparing and also contrasting the 2 elements.



1. What are transition metals?

2. Define properties of transition metals.

3. How do change metals differ from steels in teams 1 and also 2? just how are they different from all other elements?

4. Identify thelanthanides and also actinides.

Groups v Metalloids

Characteristics of teams 13 - 16 that the routine table.

· Identifyelementsin groups 13–16 the the regular table.

· perform properties that a metalloid from each of these groups.


This image represents a famous old Egyptian called Tutankhamen. Perform you watch his heavy eyeliner? Most most likely the eyeliner to be made of a mineral containing antimony. This metalloid was generally used because that makeup by Egyptians between four and also five thousand year ago. This day we know that antimony is toxic, although Tutankhamen more than likely didn’t recognize that. Antimony is uncovered in group 15 the the regular table. Team 15 is one of four groups that the routine table that containmetalloids.  

Groups 13–16

Groups 13–16 the the periodic table (orange in theFigurebelow) space the only groups that containelementsclassified asmetalloids. Unequal other teams of the routine table, i m sorry contain aspects in just one class, groups 13–16 contain aspects in at least two different classes. In addition to metalloids, they also containmetals, nonmetals, or both. Teams 13–16 fall between the transition metals (in teams 3–12) and the nonmetals calledhalogens(in group 17).


What AreMetalloids?

Metalloidsare the smallest course ofelements, containing just six members: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). Metalloids have actually some properties ofmetals(elements that deserve to conduct electricity) and also some nature of nonmetals (elements the cannot conduct electricity). For example, many metalloids have the right to conduct electricity, however not and also metals. Metalloids additionally tend to it is in shiny choose metals, yet brittle choose nonmetals. Chemically, metalloids might behave like steels or nonmetals, depending upon their number of valenceelectrons. You deserve to learn much more about particular metalloids by clicking on the element symbols in the periodic table in ~ this URL:http://www.chemicool.com/.

Q:Why walk the chemical actions of an element depend ~ above its variety of valenceelectrons?

A:Valenceelectronsare the electrons in one atom’s outerenergy levelthat may be associated inchemical reactionswith otheratoms.

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Group 13: Boron Group

Group 13 the the regular table is likewise called the boron group due to the fact that boron (B) is the very first element in ~ the top of the team (seeFigurebelow). Boron is likewise the only metalloid in this group. The various other four elements in the group—aluminum (Al), gallium (Ga), indium (In), and also thallium (Tl)—are allmetals. Team 13 facets have three valence electrons and also are fairly reactive. Every one of them aresolidsat roomtemperature.