Chemistry - metals and non metals

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Chemistry (Metals & Non Metals):

Metals

Metals have certain characteristic physical properties: they are usuallyshiny (they have

"lustre"), have a high density, are ductile andmalleable, usually have a high melting

point, are usually hard, and conductelectricity and heat. These properties are mainly

because each atom exerts onlya loose hold on its outermost electrons (valence

electrons); On the periodictable, a diagonal line drawn from boron (B) to polonium

(Po) separates themetals from the nonm etals. Most metals are grayish in color, but

bismuth ispinkish, copper is red, and gold is yellow. Some metals display more than

onecolour, a phenomenon called pleochroism.

Non metal

Anon metal is a substance that conducts heat and electricity poorly, is brittle or waxyor gaseous, and cannot be hammered into sheets or drawn into wire. Non metals gain

electrons easily to form anions . About 20% of the known chemical elements are non

metals. The oxides of nonmetals are acidic.

The nonmetals are, in order of atomic number:

hydrogen (H) carbon (C) nitrogen (N) oxygen (O) fluorine (F) phosphorus (P) sulfur (S)

chlorine (Cl) selenium (Se) bromine (Br) iodine (I) astatine (At)

Metalsand Non-Metals

Elements can be classified as metals or non-metals on the basis of their properties.

Physicalpropertiesinclude:

appearance

density

meltingandboilingpointconductivityofheatandelectricity

tensile strength (resistance to bending)

malleability (ability to roll into sheets)

ductility (ability to draw into a wire)


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Chemicalpropertiesinclude:

charge on ions formed from the element

type of bonding found in the element's oxides and chlorides

pHoftheelement's oxide

Metals are found on the left hand side of the Periodic Table while non-metals are found on the

right hand side.

Properties of Metallic and Non -Metallic Elements

Property MetallicElementsNon-

MetallicElements

Appearance

(physicalproperty)lustrous dull

Density(physicalproperty)

moderate to high low to moderate

Physical State

(25oC, 101.3kPa)

(physical property)

solid

(exceptliquidmercury)solid, liquidorgas

Melting and Boiling Point

(physical property)moderate to high wide range

Heat and Electrical Conductivity

(physical property)good poor (exceptgraphite)

Tensile Strength (resistance to

bending)

(physical property)

high brittle

Malleability (roll into sheets)

(physical property)malleable notmalleable

Ductility (draw into wire)

(physical property)ductile notductile

Charge on Ions (in general)*

(chemical property)forms positive ions forms negative ions

Bonding in oxides and chlorides

(chemical property)usuallyionic** covalent

pH of oxides

(chemical property)usually basic*** usually acidic

*some non-metals can form positive or negative ions, eg, H+

and H-


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The Various Kinds of Metals

The Various Kinds of Metals are as shown below:

Properties of Metals

Physical State : Metals are solids at room temp with the exception of mercury and

gallium which are liquids at room temp.

Summary of the Reaction of Metals with Air Water and Acids


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The Reactivity Series of Metals

Physical State

Physical State

Metals are solids at room temperature with the exception of mercury and gallium,

which are liquids at room temperature.

Lustre

Metals have the quality of reflecting light from its surface and can be polished e.g.,

gold, silver and copper.

Malleability

Metals have the ability to withstand hammering and can be made into thin sheets

known as foils.

Ductility

Metals can be drawn into wires. 100 gm of silver can be drawn into a thin wire about

200 meters long.

Hardness

All metals are hard except sodium and potassium, which are soft and can be cut with a

knife.

Valency

Metals have 1 to 3 electrons in the outermost shell of their atoms.


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Conduction

Metals are good conductors because they have free electrons. Silver and copper are

the two best conductors of heat and electricity. Lead is the poorest conductor of heat.

Bismuth, mercury and iron are also poor conductors

Density

Metals have high density and are very heavy. Iridium and osmium have the highest

densities where as lithium has the lowest density.

Melting and Boiling Point

Metals have high melting and boiling point. Tungsten has the highest melting point

where as silver has low boiling point. Sodium and potassium have low melting points.

Electropositive Character

Metals are elements that have a tendency to lose electrons and form cations.

Theynormally do notacceptelectrons.

To summarize: metals are electropositive in nature, lustrous, malleable, ductile, good

conductors of heat and electricity and generally form basic or amphoteric oxides with

oxygen.

Physical Properties of Non-metals

Physical State

Most of the non-metals exist in two of the three states of matter at room

temperature: gases (oxygen) and solids (carbon). These have no metallic lustre, and do

not reflect light.

Nature

NatureNon-metals are very brittle, and cannot be rolled into wires or pounded into sheets.

Conduction

They are poor conductors of heat and electricity.


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Electronegative Character

Electronegative Character

Non-metals have a tendency to gain or share electrons with other atoms. They are

electronegative in character.

Reactivity

They generally form acidic or neutral oxides with oxygen.

Comparative Properties of Metals and Non -Metals

A detailed comparison of properties of metals and non -metals is given in table.

Property Metals Non-metals

Stateofmatter These are usually solid, except

mercury, which is a liquid at

room temperature. Gallium

and Caesium melt below 30

. So if room temperature is

around 30 , they may also

be in liquid state

These exist in all the

three states. Bromine is

the only liquid.

Density They usually have high density,

except for sodium, potassium,

calcium etc.

Their densities are

usually low.

Meltingpoint They usually have a highmelting point except mercury,

cesium, gallium, tin, lead.

Their melting points arelow.

Boilingpoint Their boiling points are usually

high.

Their boiling points are

low.

Hardness They are usually hard, except

mercury, sodium, calcium,

potassium, lead etc.

They are usually not

hard. But the exception

is the non-metal

diamond, the hardest

substance.

Malleability They can be beaten into thin

sheets.

They are

generallybrittle.

Ductility They can be drawn into thin

wires, except sodium,

potassium, calcium etc.

They cannot be drawn

into thin wires.

Conductionofheat They are good conductors of

heat.

They are poor

conductors of heat.


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Conductionofelectricity They are good conductors of

electricity.

They are non-

conductors, except for

carbon in the form of

graphite and the gas

carbon.

Lustre Newly cut metals have high

lustre. Some

gettarnishedimmediately.

Usually not lustrous,

except iodine and

diamond - the most

lustrous of all the

substances.

Alloyformation Theyformalloys. Generally, they do not

form alloys. However

carbon, phosphorus,

sulphur etc. can be

present in some alloys.

Tenacity These usually have high tensile

strength except sodium,

potassium, calcium, lead etc.

These have low tensile

strength.

Brittleness They are hard but not brittle,

except zinc at room

temperature.

They are

generallybrittle.

Electronicconfiguration They usually have 1, 2 or 3

electrons in their valence shell.

The greater the number of

shells and lesser the number of

valence electrons, the greater

is the reactivity of the metal.

They usually have 4, 5, 6

or 7 electrons in the

valence shell. If it has 8

electrons, it is called a

noble gas. Lesser the

number of shells and

greater the number of

valence electrons,

greater is the reactivity

of the non-metal.

Ionization They always ionize by losing

electrons:

They always ionize by

gaining electrons:

Chargeofions Positivelycharged. Negativelycharged.

Typeofvalency Metalsalwaysexhibitelectroval

ency.

Non-metal exhibit both

electrovalency

orcovalency.

Depositionduringelectrol

ysis

They are always deposited at

the cathode.

They are always

deposited at the anode.

Redoxreaction These lose electrons and hence These gain electrons


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get oxidized. and hence get reduced.

Redoxagents They are reducingagents. They are

oxidizingagents.

Natureofoxides They generally form basic

oxides, some of which are also

amphoteric, such as aluminium

oxide, zinc oxide, lead oxide

etc.

They generally form

acidic oxides. Some

oxides are neutral, such

as nitrous oxide, nitric

oxide, carbon monoxide

water etc.

Hydrides They usually do not form

hydrides except those of

sodium, potassium and

calcium.

They do formhydrides,

e.g. NH3, PH3, HCl, HBr,

HI, H2S, H2O etc.

Atomicity These are alwaysmonatomic. These can be mono, di,

tri, or polyatomic.Solubility They do not dissolve in

solvents except by chemical

action.

They dissolve in

solvents and can be re-

obtained by

evaporation. Example:

Sulphurincarbondisulphi

de.

Actionwithchlorine They produce chlorides, which

are electrovalent.

They produce chlorides,

which are covalent.

Actionwithdiluteacids On reaction with dilute acids

they give respective salt and

hydrogen.

They do not react with

dilute acids.

Applications

Some metals and metal alloys possess high structural strength per unit mass, making

them useful materials for carrying large loads or resisting impact damage. Metal alloys

can be engineered to have high resistance to shear, torque and deformat ion. However

the same metal can also be vulnerable to fatigue damage through repeated use orfrom sudden stress failure when a load capacity is exceeded. The strength and

resilience of metals has led to their frequent use in high -rise building and bridge

construction, as well as most vehicles, many appliances, tools, pipes, non -illuminated

signs and railroad tracks.

The two most commonly used structural metals, iron and aluminium, are also the most

abundant metals in the Earth's crust.[6]


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Metals are good conductors, making them valuable in electrical appliances and for

carrying an electric current over a distance with little energy lost. Electrical power grids

rely on metal cables to distribute electricity. Home electrical systems, for the most

part, are wired with copper wire for its good conducting properties.

The thermal conductivity of metal is useful for containers to heat materials over a

flame. Metal is also used for heat sinks to protect sensitive equipment from

overheating.

The high reflectivity of some metals is important in the construction of mirrors,

including precision astronomical instruments. This last property can also make metallic

jewelry aesthetically appealing.

Some metals have specialized uses; radioactive metals such as uranium and plutonium

are used in nuclear power plants to produce energy via nuclear fission. Mercury is a

liquid at room temperature and is used in switches to complete a circuit when it flows

over the switch contacts. Shape memory alloy is used for applications such as pipes,

fasteners and vascular stents.

Chemistry - metals and non metals

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