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CHEMISTRY FORM 4CHAPTER 2 THE STRUCTURE OF AN ATOMTIME : 830 – 1000 PM

2.1 Matter

1. Matter is anything that occupies space and has mass.

2. The particle theory of matter states that matter is made up of a largenumber of tiny and discrete particles.

Solid Liquid !"S#!$% !&d

'olu(%

Fi)%d Fi)%d *u+ ,ollo-

+#% "#!$% o,.o&+!i&%/

F!/ A$!/+ ,/o(

%!.# o+#%/

M!&&%/ P!. %d i& O/d%/lM!&&%/

P!. %d .lo"%l*u+ &o+ i& o/d%/l(!&&%/

Mo % i& /!&do((o+io&

'i*/!+io& Ro+!+io&

'i*/!+% 'i*/!+% !&d/o+!+%

'i*/!+% !&d/o+!+%

Co($/%""io& C!&&o+ C!&&o+ *%

.o($/%""%d %!"il

C!& *% do&%

%!"il

Try to draw arrangement for solid, liquid and gaseous atoms in the box below.

Solid Liquid Gases

i,,u"io& 5 6/o-&i!& Mo+io&

1. Diffusion is a process of spreading of a substance from a region of highconcentration to a region of low concentration.

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2. The rate for diffusion for solid, liquid and gases are totally different.Compared the situation below,

Diffusion of solid – After a few days

Diffusion of liquid – After a few hours

Diffusion of gases – After a few minutes

3. rownian motion is the physical phenomenon that tiny particles immersedin a fluid mo!e about randomly.

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". rownian motion only applied for #

$%amples of rownian mo!ement are

A7 (o %(%&+ o, "(o % $!/+i.l%" i& !i/

67 (o %(%&+ o, $oll%& /!i&" i& -!+%/

2.2 Atom, molecule and ions

A+o("

A7 &n atom is the smallest particle characteri'ing a chemical element.67 &n atom has no chargeC7 $%ample of atom ( )elium, )ydrogen

Mol%.ul%

&. & molecule is the smallest particle in a chemical element or compoundthat has the chemical properties of that element or compound.

. Molecules are made up of atoms that are held together by chemicalbonds.

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Io&"

&. &n ion is an atom or molecule which has lost or gained one or moreelectrons, ma*ing it positi!ely or negati!ely charged.

. & negati!ely charged ion, which has more electrons in its electron shellsthan it has protons in its nuclei, is *nown as an anion.

C7 & positi!ely charged ion, which has fewer electrons than protons, is *nownas a cation.

2.3 Chemical Structure of an Atom

1. &tom consists of electrons surrounding a nucleus that contains protons

and neutrons.2. $lectrons are arranged around the nucleus in energy le!els or shells.3. The mass of an atom is concentrated in nucleus which contained the

protons and neutrons.". The nucleus is positi!ely charged because of the presence of protons

which are positi!ely charged and the neutrons are neutral.

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+. The atom is neutral because the number of protons and the number of

electrons are equal.

Subatomicarticles

Symbol

!elati"emass

!elati"echarge

Proton P 1 Neutron N 1 0Electron e - 1/1837 0 -1

H%!+i& !&d Cooli& P/o.%""

E)!($l%: aphthalene

T/ +o d/!- ! .u/ % /!$# o, &!$#+#!l%&% .ooli& $/o.%"" !&d +#% "%+ u$,o/ +#i" %)$%/i(%&+7

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A Naphthalene is in solid state at any temperature below its melting point.

he particles are !ery closely pac"ed together in an orderly manner.he #orces between the particles are !ery strong. he particles can only !ibrate at a #i$ed

position.

A#$%s the naphthalene is heated& heat energy is con!erted to "inetic energy.'inetic energy increases and the molecules !ibrate #aster about their #i$ed positions and thetemperature increases.

$ Naphthalene is in solid state at any temperature below its melting point.

he particles are !ery closely pac"ed together in an orderly manner.he #orces between the particles are !ery strong. he particles can only !ibrate at a #i$ed

position.

$#% Naphthalene e$ists in both solid and li(uid states.

he temperature remains constant because the heat that supplied to naphthalene is used too!ercome the #orces o# attraction that hold the particles together.

he constant temperature is called the melting point.he heat energy that absorbed to o!ercome the intermolecular #orces is named as the latent

heat o# #usion.

%%ll the naphthalene has completely melted.)olid naphthalene has turned into li(uid.

%#D Naphthalene is in li(uid state.%s the li(uid naphthalene is heated& the molecules gain more heat energy and the temperaturecontinues to increase.

he particles mo!e #aster and #aster because their "inetic energy is increasing.

D Naphthalene still e$ists in li(uid state. Naphthalene molecules ha!e recei!ed enough energy to o!ercome the #orces o# attraction between the particles in the li(uid.)ome o# the naphthalene molecules start to mo!e #reely and li(uid naphthalene begin tochange into gasha!e recei!ed enough energy to o!ercome the #orces o# attraction between the

particles in the li(uid. )ome o# the naphthalene molecules start to mo!e #reely and li(uidnaphthalene begin to change into gas

D#& Naphthalene e$ists in both li(uid and gaseous states.

he temperature remains unchanged.

he is because the heat energy absorbed is used to o!ercome the intermolecular #orces between the particles o# the li(uid rather than increase the temperature o# the li(uid.

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his constant temperature is the boiling point.

&%ll the naphthalene has turn into gas.

'he gas particles continue to absorb more energy and mo!e #aster.he temperature increases as heating continues.

he substance e$ists as both li(uid and solid.he temperature remains constant until all the li(uid changes to solid.his is because the energy released is the same as the energy lost to the surroundings during

cooling.his constant temperature is the #ree*ing point.he heat energy that releases during this #ree*ing process is called the latent heat o# #usion.

T%ll the li(uid #ree*es into solid. he particles are now closely pac"ed in an orderly manner.

T#(+nce all the li(uid has become solid& the temperature #alls once again until it reaches roomtemperature. he substance is in the solid state here.

( he substance reaches room temperature and remain at this temperature as long as the roomtemperature remain the same.

SUPERCOOLIN

This happens when cooling of naphthalene is conducting. The temperature of thenaphthalene drops rapidly to a lower temperature and then raised bac* to a

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higher temperature.

-hy this is happen#

17 No % %& #%!+i& 727 9i+#ou+ "+i//i& u&i,o/(l 737 T#% .ooli& i" &o+ u&i,o/(7

).* +S T -&

The isotopes of an element ha!e the "!(% &u(*%/ o, $/o+o&" but di,,%/%&+&%u+/o& &u(*%/ due to different numbers of neutrons. n an atom in the neutralstate, the number of electrons also equals the number of protons.

/or e%ample, the carbon013 and carbon01"

The carbon013 ha!e electrons protons and ha!e 4 neutrons.

The carbon01" ha!e electrons protons and ha!e 5 neutrons .

I"o+o$% U"%

Carbon01"

radiometric dating( determination of age of carbon0containingartefacts up to about 46,666 years

aturally occurring radioisotope

Chlorine03

measurement of sources of chloride and determining the age ofwater up to about 2 million years old

aturally occurring radioisotope

7odium02"

location of lea*s in water pipes, studies of body electrolytessotope prepared in a nuclear reactor

Cobalt0 6 cancer treatment as tumour cells tend to be more susceptible toradiation than other cells

odine0131

Medical tracer to study 8 treat the thyroid gland 8 used in thediagnosis of adrenal medullary 8 for imaging suspected neural crestand other endocrine tumours

sotope prepared in a nuclear reactor

http://www.ausetute.com.au/carbon14.htmlhttp://www.ausetute.com.au/carbon14.htmlhttp://www.ausetute.com.au/carbon14.htmlhttp://www.ausetute.com.au/carbon14.html

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