Properties of Isotope

7/27/2019 Properties of Isotope

1/20

Properties of IsotopeNumber of proton equalNumber of neutron differenceChemical properties samePhysical properties difference

How to RMM

Find the relative molecular mass of carbon dioxide.

[ JAR: C = 12; O = 16 ]

Answer:

The formula of carbon dioxide = CO2

Relative molecular mass of CO2 = 1 x 12 + 2 x 16 = 44


2/20

Element

ProtonNumber

NumberofElectron

ElectronArrangement

Hydrogen 1 1 1

Helium 2 2 2

Lithium 3 3 2.1

Beryllium 4 4 2.2

Boron 5 5 2.3

Carbon 6 6 2.4

Nitrogen 7 7 2.5

Oxygen 8 8 2.6

Fluorine 9 9 2.7

Neon 10 10 2.8

Sodium 11 11 2.8.1

Magnesium 12 12 2.8.2

Aluminium 13 13 2.8.3

Silicon 14 14 2.8.4

Phosphorus 15 15 2.8.5

Sulphur 16 16 2.8.6

Chlorine 17 17 2.8.7

Argon 18 18 2.8.8

Potassium 19 19 2.8.8.1

Calcium 20 20 2.8.8.2


3/20

EMPIRICAL FORMULA

1) IRON OXIDE

In a chemical reaction, 4.23g of iron reacts completely with 1.80g of oxygen gas, producing iron

oxide. Calculate the empirical formula of iron oxide. [Relative atomic mass: Iron = 56; Oxygen = 16]

Answer:

Element Fe OMass 4.23g 1.80g

Number of mole 4.2356=0.0755 1.8016=0.1125

Simple ratio 0.07550.0755=1 0.11250.0755=1.5

Ratio in round

number

2 3

The empirical formula of iron oxide = Fe2O3

2) MG, S, O

Determine the empirical formula of a compound which has a percentage of composition Mg: 20.2%,

S: 26.6%, O: 53.2%. [Relative atomic mass: Mg = 24; S = 32; O = 16]

AnswerElement Mg S O

Percentage 20.2% 26.6% 53.2%

Mass in 100g 20.2g 26.6g 53.2g

Number of mole 20.224=0.8417mol 26.632=0.8313mol 53.216=3.325mol

Simple ratio 0.84170.8313=1 0.83130.8313=1 3.3250.8313=4

The empirical formula of the compound is MgSO4


4/20

3)HYDROCARBON

From an experiment, a scientist found that a hydrocarbon contains 85.7% of carbon according to its

mass. Find the empirical formula of the hydrocarbon. [Relative atomic mass: Carbon = 12; Hydrogen

= 1]

Answer:

Element C HPercentage 85.7% 14.3%

Mass in 100g 85.7g 14.3g

Number of mole 85.712=7.142mol 14.31=14.3mol

Simple ratio 7.1427.142=1 14.37.142=2

The empirical formula of the hydrocarbon = CH2

MOLECULAR MASS

Given that the empirical formula of benzene is CH and its relative molecular mass is 78. Find the

molecular formula of benzene. [Relative Atomic Mass: Carbon: 12; Hydrogen: 1]

Answer:

Let's say the molecular formula of benzene is CnHn.

The relative molecular mass of CnHn

= n(12) + n(1)

= 13n

13n = 78

n = 78/13 = 6

Therefore, the molecular formula of benzene

= C6H6


5/20

Percentage of Composition of a Compound

Calculate the percentage of composition of DDT (C14H9Cl5). [Relative atomic mass:

Carbon = 14; Hydrogen = 1; Chlorine = 35.5]

Answer:Relative molecular mass of DDT=14(12)+9(1)+5(35.5)

=354.5

Percentage of carbon=14(12) / 354.5 100%

=47.4%

Percentage of hydrogen= 9(1) / 354.5 100%

=2.5%

Percentage of chlorine= 5(35.5) / 354.5 100%

=50.0%


6/20

Example 4 Formulae of Acid

a. Hydrochloric acid

b. Sulphuric acid

c. Nitric acid

d. Ethanoic acid

e. Phosphoric acid
http://2.bp.blogspot.com/-8_SRI_4Ch9c/UORN1xeBzwI/AAAAAAAAAlY/k64eJ4NHuMk/s1600/Picture10.pnghttp://4.bp.blogspot.com/---F9nLOJuko/UORN3uASYbI/AAAAAAAAAlo/jMSpEhxtuTI/s1600/Picture12.pnghttp://3.bp.blogspot.com/-bMB1YQZeuOs/UORN0F5dDJI/AAAAAAAAAlI/bW7N_GI_ggY/s1600/Picture8.pnghttp://3.bp.blogspot.com/-J4R0Qpe3lZw/UORN02MDS0I/AAAAAAAAAlM/dwxrXcWIQFg/s1600/Picture9.pnghttp://2.bp.blogspot.com/-8_SRI_4Ch9c/UORN1xeBzwI/AAAAAAAAAlY/k64eJ4NHuMk/s1600/Picture10.pnghttp://4.bp.blogspot.com/---F9nLOJuko/UORN3uASYbI/AAAAAAAAAlo/jMSpEhxtuTI/s1600/Picture12.pnghttp://3.bp.blogspot.com/-bMB1YQZeuOs/UORN0F5dDJI/AAAAAAAAAlI/bW7N_GI_ggY/s1600/Picture8.pnghttp://3.bp.blogspot.com/-J4R0Qpe3lZw/UORN02MDS0I/AAAAAAAAAlM/dwxrXcWIQFg/s1600/Picture9.pnghttp://2.bp.blogspot.com/-8_SRI_4Ch9c/UORN1xeBzwI/AAAAAAAAAlY/k64eJ4NHuMk/s1600/Picture10.pnghttp://4.bp.blogspot.com/---F9nLOJuko/UORN3uASYbI/AAAAAAAAAlo/jMSpEhxtuTI/s1600/Picture12.pnghttp://3.bp.blogspot.com/-bMB1YQZeuOs/UORN0F5dDJI/AAAAAAAAAlI/bW7N_GI_ggY/s1600/Picture8.pnghttp://3.bp.blogspot.com/-J4R0Qpe3lZw/UORN02MDS0I/AAAAAAAAAlM/dwxrXcWIQFg/s1600/Picture9.pnghttp://2.bp.blogspot.com/-8_SRI_4Ch9c/UORN1xeBzwI/AAAAAAAAAlY/k64eJ4NHuMk/s1600/Picture10.pnghttp://4.bp.blogspot.com/---F9nLOJuko/UORN3uASYbI/AAAAAAAAAlo/jMSpEhxtuTI/s1600/Picture12.pnghttp://3.bp.blogspot.com/-bMB1YQZeuOs/UORN0F5dDJI/AAAAAAAAAlI/bW7N_GI_ggY/s1600/Picture8.pnghttp://3.bp.blogspot.com/-J4R0Qpe3lZw/UORN02MDS0I/AAAAAAAAAlM/dwxrXcWIQFg/s1600/Picture9.png


7/20

f. Carbonic acid
http://2.bp.blogspot.com/-tFhuDfNo8Y4/UORN22ByaYI/AAAAAAAAAlg/TG6pW1vUEgM/s1600/Picture11.png


8/20

Group 18 Elements - Noble Gases

1. The "Noble Gases" are the last group in the Periodic Table, they alsoknown as "inert gas", due to their non-reactive behavior.

2. This group consist of six elements, namely Helium, Neon, Argon,

Kripton, Xenon and Radon.

3. They are non-metallic, colourless gases at room temperature and

pressure with very low melting points and boiling points.

4. They form 1% of air, and most of this is argon.

5. The size of atom increases down the group, due to the increase number

of electron shell.

Name Proton number Electron arrangement Melting point Boiling pointHelium 2 2 -270C -269C

Neon 10 2.8 -249C -246C

Argon 18 2.8.8 -189C -186C

Krypton 36 2.8.18.8 -157C -152C

Xenon 54 2.8.18.18.8 -112C -108C

Radon 86 2.8.18.32.18.8 -71C -62C
http://2.bp.blogspot.com/-6iSugK1DD8Q/UQTDFKMSoJI/AAAAAAAAAu4/llhYuTZyQsU/s1600/noblegas.png


9/20

Physical PropertiesSolubility and Conductivity

1. All noble gas are insoluble in water.

2. They are not conductor of heat and electricity.

Melting Point and Boiling Point1. As show in the table above, the melting and boiling point of noble gases

are very low.

2. This is because all noble gases exist as monoatoms. The force in between

all these atoms is the weak van de Waals' Force.

3. Therefore very little energy is needed to overcome this force during

melting and boiling.

Density1. The density of noble gases are very low.2. Nevertheless, the density increases steadily down the group.

3. Density of a substance is given by the equation "Density=Mass/Volume".

4. Down the group, both the mass and the volume increase, but increase of

mass is faster than the volume, hence the density increases down the

group.


10/20

Chemical Properties

1. All the noble gases are non-reactive elements.

2. This is because their valence shell is full of electrons.

3. In the chemical world, an atom is in the chemically most stable state if

their valence shell is full with eight electrons (or 2 electrons for the first

shell.).

4. Therefore all noble gases do not react with other elements, due to their

stable electronic structure.

5. They exist as single atoms, that is they are monatomic.


11/20

Group 1 Elements - Alkali Metals

1. The Group 1 metals is called the Alkali Metals.

2. This is because they form oxides and hydroxides that dissolve in water

to give alkaline solutions.

3. As shown in the diagram on the right, elements in this group are

lithium, sodium, potassium, rubidium, caesium and francium.

4. They are the first element of a period, with one valence electron.

5. This similarity (1 valence electron) makes them chemically behave in a

similar manner.

6. All alkali metals are very reactive. They must be stored in oil prevent

reaction with oxygen or water vapour in air.

Physical Properties of Alkali MetalsName Proton numberElectron arrangementmelting pointboiling pointDensity g/cm3Lithium 3 2.1 180C 1342C 0.53

Sodium 11 2.8.1 98C 883C 0.97

Potassium 19 2.8.8.1 63C 759C 0.86

Rubidium 37 2.8.18.8.1 39C 688C 1.48

Caesium 55 2.8.18.18.8.1 29C 671C 1.87

Francium 87 2.8.18.32.18.8.1 27C 677C > 1.87

1. All Group 1 metal exist as solid at room temperature and hence have all the typical

metallic properties, such as:

a. good conductors of heat
http://2.bp.blogspot.com/-cJExvjBI0RY/UQTsL2FJXmI/AAAAAAAAAvQ/FE_vMF7xgJA/s1600/Almetal.png


12/20

b. good conductors of electricity,

c. high boiling points,

d. shinny surface (but rapidly tarnished by air oxidation).

2. Nevertheless, Group 1 metals also show some non-typical metallic properties, such

as:

a. low melting points,

b. low density (first three float on water),

c. very soft (easily squashed, extremely malleable, can be cut by a knife).

Important trends down the group:

1. size of atoms increases

2. the melting point and boiling point decrease

3. the density increases.4. the hardness decreases.

Size of Atom1. Down the group, the size of atom increases.

2. This is due to the increase of number of electron shells.

3. Atom with more shells is bigger than atom with less shells.
http://2.bp.blogspot.com/-1gL2yo6zrtA/UQXq0aInvcI/AAAAAAAAAvw/a8fwFRKAmLg/s1600/group1-03.pnghttp://3.bp.blogspot.com/-bDG4iJbI3KU/UQXqoLtwG7I/AAAAAAAAAvo/7KKpdmNaFgE/s1600/size-02.pnghttp://2.bp.blogspot.com/-1gL2yo6zrtA/UQXq0aInvcI/AAAAAAAAAvw/a8fwFRKAmLg/s1600/group1-03.pnghttp://3.bp.blogspot.com/-bDG4iJbI3KU/UQXqoLtwG7I/AAAAAAAAAvo/7KKpdmNaFgE/s1600/size-02.png


13/20

Boiling Point and Melting Point1. The melting point and boiling point generally decrease down the group.

2. All the atoms of Group 1 metals are bonded together by a force called metallic bond.

3. The strength of metallic bond depends on the distance between the atoms. Thecloser the atoms, the stronger the bond.

4. Down the group, the size of the atoms increases, causing the distance of the atoms

increases.

5. As the distance between the atoms increases, the metallic bond between the atoms

decreases.

6. Therefore, less energy is needed to overcome the metallic bond during melting

process.

7. Consequently, the melting point of Group 1 metal decreases down the group.

Density1. The densities of Group 1 metals are low compare with the other metals.

2. The densities of the first 3 elements (Lithium, Sodium and Potassium) are lower than

water. Thus, they can float on the surface of water.

3. Nevertheless, the density increases steadily down the group.

4. Density of a substance is given by the equation "Density=Mass/Volume".

5. Down the group, both the mass and the volume increase, but increase of mass is

faster than the volume, hence the density increases down the group


14/20

Chemical Properties of Alkali Metals

1. Group 1 metals are very reactive metals.

2. They all show the same chemical properties.

3. They can react with water and non-metal such as oxygen and chlorine to form a

new compound.

4. The table to the right shows the electron arrangement of all the Group 1 metals. All

the atoms of Group 1 metal consist of 1 valence electron.

5. When an alkali metal atoms react, it loses the valence electron to form a positively

charged ion.

Example:LiLi++eNaNa++eKK++e

6. They tend to react mainly with non-metals to form ionic compounds.

Safety Precaution1. Alkali metals are very reactive.

2. Therefore it must be kept in paraffin oil to prevent them from reacting with oxygen

and water vapour in the air.

3. We must avoid to hold group 1 metals with bare hand because they may react with

water on our hand.

4. We must wear safety goggles and gloves during handling experiment involving

group 1 metal.
http://4.bp.blogspot.com/-Wl20tzlJC6s/UQYcu0jTT2I/AAAAAAAAAwI/MrSAnaIe1w4/s1600/Picture1.pnghttp://4.bp.blogspot.com/-Wl20tzlJC6s/UQYcu0jTT2I/AAAAAAAAAwI/MrSAnaIe1w4/s1600/Picture1.pnghttp://4.bp.blogspot.com/-Wl20tzlJC6s/UQYcu0jTT2I/AAAAAAAAAwI/MrSAnaIe1w4/s1600/Picture1.png


15/20

Solubility of the Oxide, Hydroxide and Salt of AlkaliMetals

1. All the oxide and hydroxide of group 1 metal are soluble in water to forman alkali solution.

2. All the salts (salt of chloride, nitrate, sulphate, carbonate....) of group 1

metals are soluble in water. The solutions formed are neutral.
http://3.bp.blogspot.com/-vj7ZivNCgjs/UQcn2UKDL6I/AAAAAAAAAxY/JIl1XmLG37k/s1600/Picture1.png


16/20
http://1.bp.blogspot.com/-jpqPtN0lA7k/UQcovpg2JTI/AAAAAAAAAxg/jfqtp3wyKIA/s1600/Picture2.png


17/20

Group 17 Elements - Halogens

1. Group 17 elements are typical non-metals and also known as halogens.

2. The elements in this group are fluorine. chlorine, bromine, iodine and astatine.

3. In nature, all halogens exist as diatomic molecules. They are written as F2, Cl2, Br2, I2 and

As2.

4. Most of the halogens exist in the nature as halide salts.

5. Halide is the name given to the ion of halogens. Table below shows the corresponding halide

of the halogen.

Halogen HalideFluorine Fluoride

Chlorine CHloride

Bromine Bromide

Iodine Iodide
http://1.bp.blogspot.com/-FvS0nQt4I1g/UQhxCrjqxjI/AAAAAAAAAyM/HBim55BNgKc/s1600/halogen.pnghttp://www.blogger.com/share-post.g?blogID=4800886314390844338&postID=1221142778533037571&target=email


18/20

Physical Properties of Halogens1. All group 17 elements are non-metals. Therefore they are heat and electricity

insulator.

2. Table below shows the electron arrangement and physical properties of group 17

elements.

Name ProtonNumberElectronarrangement Colour

Meltingpoint

Boilingpoint

Fluorine9 2.7 pale yellow gas -220C -188CChlorine 17 2.8.7 Yellowish green gas -102C -34C

Bromine 35 2.8.18.7 dark red liquid, brownvapour

-7C 59C

Iodine 53 2.8.18.18.7 black solid, purple vapour 114C 184CAstatine 85 2.8.18.32.18.7 black solid, dark vapour 302C 380C

Size of Atom and Density

1. The atomic size of group 17 elements increases down the group.

2. This is due to the increase of number of electron shell down the group.

3. The density of group 17 elements is also increases down the group.

4. This is because the rate of increment of the atomic mass is higher than the rate of

increment of the volume.
http://2.bp.blogspot.com/-QiA2zap8hyc/UQhx9p9VDnI/AAAAAAAAAyU/JYQ5LGuDWkc/s1600/AtomicRadius3.png


19/20

Melting Point and Boiling Point

1. As shown in the graph to the right, the melting points and boiling increase steadily

down the group.

2. The physical state at room temperature also change from gas to liquid and then to

solid.

3. This is because the intermolecular attractive force (van der Waals force) increase

with increasing size of atom or molecule.
http://3.bp.blogspot.com/-94H_Mt6HK4c/UQhyHi0ammI/AAAAAAAAAyc/khSJMwXIeP0/s1600/BPointHalogen.pnghttp://1.bp.blogspot.com/-GWnQszFd-Fk/UQhyKUeDY5I/AAAAAAAAAyk/kL8Jz4ycchY/s1600/MPointHalogen.pnghttp://3.bp.blogspot.com/-94H_Mt6HK4c/UQhyHi0ammI/AAAAAAAAAyc/khSJMwXIeP0/s1600/BPointHalogen.pnghttp://1.bp.blogspot.com/-GWnQszFd-Fk/UQhyKUeDY5I/AAAAAAAAAyk/kL8Jz4ycchY/s1600/MPointHalogen.png


20/20

Chemical Properties of Halogens1. Group 17 elements are very reactive non-metals.

2. The atoms all have 7 valence electrons, makes them have very similar chemical properties.

3. During chemical reaction, the atom gains one electron to form an ion with charge of -1.

4. The reactivity of group 1 decreases down the group.

5. All group 17 elements are poisonous.

6. Astatine is very radioactive.

Safety Precaution

1. Fluorine, chlorine and bromine gases are poisonous.

2. Therefore all the experiments involving these gases should be carried out in a fume

chamber.

3. The experiments involve fluorine are nor done in school.

4. This is because fluorine is so reactive that it will react with most of the substance it comes

into contact with.

5. It is very difficult to conduct experiments involving fluorine.
http://4.bp.blogspot.com/-wXcmJT_wHR0/UQi4PY61lfI/AAAAAAAAAzA/mEWocwDPuic/s1600/IonisationFluorine.png

Properties of Isotope

Documents

Transcript of Properties of Isotope