compare and contrast

Grouping of matter (compare and contrast)

Chemical compounds may be classified according to several different criteria. One common method is based on the specific elements present. For example, oxides contain one or more oxygen atoms, hydrides contain one or more hydrogen atoms, and halides contain one or more halogen (Group 17) atoms. Organic compounds are characterized as those compounds with a backbone of carbon atoms, and all the remaining compounds are classified as inorganic. As the name suggests, organometallic compounds are organic compounds bonded to metal atoms.

                       

            The different abilities of the various atoms to combine to form compounds can best be understood in terms of the periodic table. The periodic table was originally constructed to represent the patterns observed in the chemical properties of the elements (see chemical bonding). That is to say, as the science of chemistry developed, it was observed that elements could be grouped according to their chemical reactivity. Elements with similar properties are listed in vertical columns of the periodic table and are called groups. As the details of the atomic structure were revealed, it became clear that the position of an element in the periodic table correlates with the arrangement of the electrons possessed by the atoms of that element (see atom). In particular, it was observed that the electrons that determine the chemical behaviour of an atom are those in its outermost shell. Such electrons are called valence electrons.

Alkali metals: The alkali metals make up Group 1 of the table, and comprise lithium (Li) through francium (Fr). These elements have very similar behavior and characteristics. Hydrogen is Group 1, but it exhibits few characteristics of a metal and is often categorized with the nonmetals.

Alkaline earth metals: The alkaline earth metals make up Group 2 of the periodic table, from beryllium (Be) through radium (Ra). The alkaline earth metals have very high melting points and oxides that have basic alkaline solutions.

Lanthanides: The lanthanides comprise elements 57 — lanthanum (La), hence the name of the set — through 71, lutetium (Lu). They, along with the actinides, are often called "the f-elements" because they have valence electrons in the f shell.

Actinides: The actinides comprise elements 89, actinium (Ac), through 103, lawrencium (Lr). They, along with the lanthanides, are often called "the f-elements" because they have valence electrons in the f shell. Only thorium (Th) and uranium (U) occur naturally with significant abundance. They are all radioactive.

Transition metals: The transition elements are metals that have a partially filled d subshell and comprise Groups 3 through 12 and the lanthanides and actinides.

Post-transition metals: The post-transition elements are aluminum (Al), gallium (Ga), indium (In), thallium (Tl), Tin (Sn), lead (Pb) and bismuth (Bi). As the name implies, these elements have some of the characteristics of the transition metals, but they tend to be softer and conduct more poorly than the transition metals.

Metalloid: The metalloids are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po). They sometimes behave as semiconductors (B, Si, Ge) rather than as conductors. Metalloids are also called "semi-metals" or "poor metals."

Nonmetals: The term "nonmetals" is used to classify hydrogen (H), carbon (C), nitrogen (N), phosphorus (P), oxygen (O), sulfur (S) and selenium (Se).

Halogens: The halogen elements are a subset of the nonmetals. They comprise Group 17 of the periodic table, from fluorine (F) through astatine (At). They are generally very chemically reactive and are present in the environment as compounds rather than as pure elements.

Noble gases: The inert, or noble, gases comprise Group 18. They are generally very stable chemically and exhibit similar properties of being colorless and odorless.

  

The chemical elements can be classified in many different ways. The most fundamental division of the elements is into metals, which constitute the majority of the elements, and nonmetals. The typical physical properties of metals are lustrous appearance, malleability (the ability to be pounded into a thin sheet), ductility (the ability to be drawn into a wire), and efficient thermal and electrical conductivity. The most important chemical property of metals is the tendency to give up electrons to form positive ions. Copper (Cu), for example, is a typical metal. It is lustrous but easily tarnishes; it is an excellent conductor of electricity and is commonly used for electrical wires; and it is readily formed into products of various shapes, such as pipes for water systems. Copper is found in many ionic compounds in the form of either the Cu⁺ or the Cu²⁺ ion.

The metallic elements are found on the left side and in the centre of the periodic table. The metals of Groups 1 and 2 are called the representative metals; those in the centre of the periodic table are called the transition metals. The lanthanoids and actinoids shown below the periodic table are special classes of transition metals.

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Metals, nonmetals, and metalloids are represented in different regions of the periodic table.

The nonmetals, which are relatively few in number, are found in the upper right-hand corner of the periodic table—except for hydrogen, the only nonmetallic member of Group 1. The physical properties characteristic of metals are absent in nonmetals. In chemical reactions with metals, nonmetals gain electrons to form negative ions. Nonmetallic elements also react with other nonmetals, in this case forming molecular compounds. Chlorine is a typical nonmetal. At ordinary temperatures, elemental chlorine contains Cl₂ molecules and reacts with other nonmetals to form molecules such as HCl, CCl₄, and PCl₃. Chlorine reacts with metals to form ionic compounds containing Cl⁻ ions.

The division of the elements into metals and nonmetals is only approximate. A few elements along the dividing line exhibit both metallic and nonmetallic properties and are called metalloids, or semimetals.

To simplify compare and contrast of matter we can make a the double bubble maps, for example magnesium and silicon.

From the double bubble maps we can see the compare and contrasct magnesium and silicon, the compare both of those are solid, have silver colour.

Reference

http://www.livescience.com/28507-element-groups.html

https://www.britannica.com/science/chemical-compound/Classification-of-compounds

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