jadual berkala bi
TRANSCRIPT
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 1/19
UNIT 3: PERIODIC TABLE
HISTORICAL DEVELOPMENT- To identify the contribution of scientists in the arrangement of elements in the Periodic
Table.- To get ideas on the arrangement of elements in the Periodic Table based on their proton
numbers.
ARRANGEMENT OF ELEMENT IN THE PERIODIC TABLEGROUP - To write the electron arrangement for atoms of elements with proton numbers 1 to 20.
PERIOD - To determine the group and period based on the electron arrangement of atoms or
otherwise.
PROPERTIES OF ELEMENTS IN THE PERIODIC TABLEGROUP 18- To explain the existence of noble gases as monoatoms and their uses.
GROUP 1 - To explain physical properties, similar chemical properties (with water, oxygen and
chlorine) and the different reactivities.
GROUP 17 - To explain physical properties, similar chemical properties (with water, sodium hydroxide
and iron) and the different reactivities.
PERIOD 3 - To explain changes in atomic size, electronegativity, metallic properties as well as oxide
properties across period 3 from left to right.
TRANSITION ELEMENTS
-
To state metallic properties of transition metals and their special characteristics.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 2/19
Advantages of Classifying the Elements in the Periodic Table
1. Elements are arranged systematically in the Periodic Table in an increasing order of proton number which enables:a. chemists to study , understand and remember the chemical and physical properties
of all the elements and compounds in an orderly manner,b. properties of elements and their compounds to be predicted based on the position
of elements in the Periodic Table,c. relationship between elements from different groups to be known.
Contribution of Scientist to the Historical Development of the Periodic Table
Scientists Discoveries
Antoine -
Substances were classified into 4 groups with similar chemical properties. J.W
Dobereiner - Substances were arranged in 3 groups.- Groups with similar chemical properties were called Triads.- Triad system was confined to some elements only.
JohnNewlands
- Elements were arranged in accending atomic mass.- Law of Octaves because similar chemical properties were repeated at every
eighth element.- This system was inaccurate because there were some elements with wrong mass
numbers.Lothar
Meyer
- The atomic volume = ( )
( )
- Plotted graph for the atomic volume against atomic mass.- Found that elements with similiar chemical properties were positioned at
equivalent places along the curve.Mendeleev - Elements were arranged in ascending order of increasing atomic mass.
- Elements with similar chemical properties were in the same group.- Empty spaces were allocated for elements yet to be discovered.- Contributor to the formation of the modern Periodic Table.
HenryMoseley
- Classified concepts of proton number and elements in accending order of increasing proton number.
- Contributor to the formation of the modern Periodic Table.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 3/19
1. Write the electron arrangement for each atom of element in the Periodic Table below.
2. Elements in the Periodic Table are arranged horizontally in increasing order of protonnumber .
3. Two main components of the Periodic Table:
i. Groupii. Period
Period
a. The vertical column of elements in the Periodic Table arranged according to thenumber of valance electron in the outermost shell of atoms is called groups.
b. There are 18 vertical columns, called Group 1, Group 2, and Group 3 until Group 18.
Number of Valence Electrons 1 2 3 4 5 6 7 8(except Helium)
Group 1 2 13 14 15 16 17 18
For atoms of elements with 3 to 8 valence electrons,the group number is: 10 + number of valence electrons.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 4/19
c. Specific name of groups: Group 1 – Alkali metals # Group 2 – Alkali-earth metals. Group 3 to 12 – Transition elements #
Group 17 – Halogens # Group 18 – Noble gases #
# The important groups that will be studied with respect to chemical andphysical properties.
d. Types of substances according to the groups:- Elements of group 1, 2 and 13 – atoms of each element have 1, 2 and 3 valence
electrons respectively are metals.- The elements of group 3 to 12 – transition
elements are metals.- The elements of Group 14, 15, 16, 17 and 18
– atoms of each element have 4, 5, 6 7 and 8valence electrons respectively are non-metals.
Period
1. The horizontal row of elements in the Periodic Table, consists of the same number of shells occupied with electrons in an atom are called period.
2. There are seven horizontal rows of elements known as period 1, 2, ....., 7 [Refer to theperiodic table] a) Period 1 – has 2 elements b) Period 2 and 3 # – have 8 elements c) Period 4 and 5 – have 18 elements d) Period 6 – has 32 elements e) Period 7 – has 23 elements
Short periods, # Period 3 will be studied in detailwith respect to physical and chemical properties
Long periods
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 5/19
EXERCISE
1. Complete the table below.
Element ProtonNumber
ElectronArrangement in
atom
Number of Valence
Electrons inatom
Group Number of Shell in atom
Period
H 1 1 1 1 1 1He 2 2 2 18 1 1Li 3 2.1 1 1 2 2Be 4 2.2 2 2 2 2B 5 2.3 3 13 2 2C 6 2.4 5 15 2 2
N 7 2.5 6 16 2 2O 8 2.6 7 17 2 2F 9 2.7 8 18 2 2
Ne 10 2.8 1 1 3 3Na 11 2.8.1 2 2 3 3Mg 12 2.8.2 3 2 3 3A1 13 2.8.3 3 3 3 3
EXERCISE
1. The diagram below shows the chemical symbols which represent elements X, Y andZ.
a. The proton number of element X is 11 and the number of proton inatom X is 11 . The number of electrons in atom X is 11 . The electronarrangement of atom X is 2.8.1 . Element X is located in Group 1 becauseatom X has one valence electron . It is Period 3 because atom X has three shells occupied /filled with electrons .
b. i. State the position of element Y in the Periodic Table. Element Y is located in Group 14 and Period 2
2 66 9
9
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 6/19
ii. Explain how you determine the position of element Y in the PeriodicTable.- The proton number of element Y is 6 and the number of proton in
atom Y is 6.
- The electron arrangement of atom Y is 2.4.- Element Y is located in Group 14 because atom Y has 4 valanceelectron.
- It is in Period 2 because atom Y has 2 shells occupied/filled withelectrons.
c. Which of the above elements show the same chemical properties? Explainyour answer.
- Element X and element Z.- Electron arrangement of atom X is 2.8.1 and electron arrangement of
atom Z is 2.8.8.1- Atom X and atom Z have the same number of valence electron.
Group 18 (Noble Gases)
1. Consist of Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) andRadon (Rn).
Elements Electron arrangement Helium 2 Neon 2.8 Argon 2.8.8
Krypton 2.8.18.8
2. They are chemically inert because the outermost shell of the atom has achieved dupletelectron arrangement for helium and octet electron arrangement for others.
3. It does not combine with other elements (does not lose, gain or share electrons).4. These gases exist as single uncombined atoms and are said to be monoatomic gases.5. Going down group 18:
a. The atomic size is increasing because the number of shells increases.b. The melting point/boiling point is very low because atoms of noble gases atoms
are attracted by weak Van der Waals forces, less energy is required to overcomethese forces. However, the melting / boiling point increases going down the groupbecause atomic size increases, causing the Van der Waal forces to increase andmore energy is required to overcome these forces.
c. The density is low and increases gradually because the mass increases greatlygoing down the group.
6. All noble gases are insoluble in water and cannot conduct electricity in all conditions.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 7/19
7. Complete the uses of noble gases in the table below:
Noble gases UsesHelium To fill weather balloons and airship Neon To fill neon light (for advertisement board) Argon To fill electrical bulb
Krypton To fill photographic flash lamp Radon To treat cancer
Group 1 (Alkali Metals)
1. Consist of Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Cesium(Cs) andFrancium(Fr).
Elements Symbol Proton Number Electron Arrangementin atom
Number of Shellsin atom
Lithium Li 3 2.1 2Sodium Na 11 2.8.1 3
Potassium K 19 2.8.8.1 4
2. Physical properties:a. Grey solid with shiny surface.b. Softer and the density is lower compared to other metals.c. Lower melting and boiling points compared to other metals.
3. Changes in physical properties going down the group:a. Atomic size increases because the number of shells increases.b. Density increases because mass increases faster than the increase in radius.c. Melting and boiling point decreases because when the atomic size increases, the
metal bonds are weaker.
4. Chemical Properties of Group 1 elements:
a. Each atom has one valence electron; the stable octet electron arrangement isachieved by releasing one valence electron.
b. All elements in Group 1 have similar chemical properties because all atoms inGroup 1 have one valence electron and achieve the stable electron arrangementby releasing its valence electron to form a positive charged ion.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 8/19
c. The reactivity of alkali metals increases going down the group.Explanation:
i. Atoms of Group 1 metals achieve a stable electron arrangement of noblegases by releasing one valence electron to form +1 charged ion.
ii.
The reactivity of Group 1 metals depends on the ability for atoms to loseelectrons; the easier it is to lose an electron, the greater the reactivity of the metal.
iii. Going down Group 1, the number of shells increases, the atomic radiusincreases and the valence electron in the outer most shell gets further away from the nucleus. The nuclei attraction on the valence electron getsweaker , the valence electron is loosely held and it is easier for theelectron to be released.
5. Chemical Reactions of Group 1 elements:a. With water
2X + 2H 2O → 2XOH + H 2, X is a metal element of Group 1
Element Observation Chemical equation Li Lithium moves slowly on the water surface. The
colourless solution formed turns red litmus to blue.2Li + H 2O → 2LiOH + H 2
Na Sodium moves quickly on the water surface and produces yellow flame. The colourless solution formed turns red litmus to blue.
2Na + H 2O → 2NaOH + H 2
K Potasium moves very quickly on the water surfaceand produce yellow flame. The colourless solution
formed turns red litmus to blue.
2K + H 2O → 2KOH + H 2
b. With chlorine gas:
2X + Cl 2 → 2XCl, X is a metal element of Group 1
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 9/19
Element Observation Chemical equation Li Lithium burns slowly with a red flame.
A white solid is produced.2Li + Cl 2 → 2LiCl
Na Sodium burns brightly with a yellow flame. A white solid is produced.
2Na + Cl 2 → 2NaCl
K Potassium burns very brightly with a purple flame. A white solid is produced.
2K + Cl 2 → 2KCl
c. With oxygen gas: (**the set-up of apparatus is similar to the reaction withchlorine gas.)
Element Observation Chemical equationLi Lithium burns slowly with a red flame.
A white solid is produced.
4Li + O 2 → 2Li 2O
Li2O + H 2O → 2LiOH Na Sodium burns brightly with a yellow flame. A white solid is produced.
4Na + O 2 → 2Na 2ONa 2O + H 2O → 2NaOH
K Potassium burns very brightly with a purple flame. A white solid is produced.
4K + O 2 → 2K 2OK2O + H 2O → 2KOH
Conclusion: Going down Group 1: Li Na K Rb Increase in reactivity
EXERCISE
1. The diagram below shows the electron arrangement for atoms P and Q.
a. i. Element P and Q are placed in the same group in Periodic Table. State the
group.- Group 1
ii. How is element P and Q kept in the laboratory? Give reason for youranswer.
- In paraffin oil - To prevent them from reacting with oxygen or water vapour in the
atmosphere.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 10/19
b. State one difference in physical properties between element X and element Y.
Melting point of element Q is lower than element P// Density of element Q ishigher than P// atomic size of Q is bigger than P
c. i. Write chemical equation for the reaction between elements P with water.
2P + 2H 2O → 2POH + H 2
ii. What is the expected change of colour when a few drops of phenolphthaleinare added into the aqueous solution of the product? Explain your answer.
- Colourless to purple/ pink - The solution formed is alkaline
iii. Between element P and element Q, which is more reactive in the reactionwith water. Explain your answer.
- Element Q is more reactive than P - The size of atom Q is greater than atom P - The valence electron of atom Q is further away from the nucleus
compared to atom P. - The attraction forces between nucleus and valence electron of atom Q
is weaker than atom P - Atom Q is easier to release the valence electron compared to atom P
d. Name one element that has the same chemical properties as P and QPotassium
Group 17 (Halogens)
1. Consist of Fluorine (F 2), Chlorine (Cl 2), Bromine (Br 2), Iodine (I 2) and Astatine (At 2)
Elements Symbol Proton Number Electron Arrangementin atom
Number of Shellsin atom
Fluorine F2 9 2.7 2Chlorine Cl 2 17 2.8.7 3Bromine Br 2 35 2.8.18.7 4
Iodine I 2 53 2.8.18.18.7 5
2. Physical Propertiesa. Does not conduct electricity in all state.b. Does not conduct heat.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 11/19
3. Changes in physical properties going down the group :-a. Physical properties change from gas (Fluorine and Chlorine) to liquid
(Bromine) and to solid (Iodine) at room temperature.b. The atomic size increases going down the group because of increase in
number of shell . c. The density is low and increases going down the group.d. The melting and boiling points are low because the molecules are attracted by
weak Van der Waals forces, and small amount of energy is required toovercome these forces. However the melting/boiling point increases goingdown the group because the increase in atomic size causes a stronger molecular forces. More energy required to overcome this forces .
e. The colour of the elements becomes darker going down the group: Fluorine(light yellow), Chlorine (greenish yellow), Bromine (Brown) and Iodine(Purplish black).
4. Chemical properties of Group 17 elementsa. All atoms of elements in Group 17 have 7 valence electron and achive a stable
octet electron arrangement by accepting one electron to form negative chargedions:
b. Chemical properties of all elements are similar because the number of valenceelectrons in atoms are the same and achieve the stable octet electronarrangement in a similar way.
c. Reactivity of halogens decreases going down the group :Explanation:
i. All the atoms of Group 17 have seven valence electrons and achieve astable octet electron arrangement by accepting one electron to form – 1charged ion or by sharing a pair of electrons.
ii. The reactivity of a halogen atom depends on the tendency of the atomto accept electron.
iii. Going down Group 17, the number of shells increases, atomic size increases.
iv. Outer shell becomes further from the nucleus.v. The strength to attract one electron into the outer most occupied shell
by the nucleus becomes weaker .vi. The strength of a halogen atom to attract electron decreases from
fluorine to astatine (electronegativity decreases)
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 12/19
vii. Exist as diatomic molecules (2 atoms of elements sharing a pair of valence electrons) to achieve stable octet electron arrangement.(Complete the electron arrangement for the atom and molecule below)
The elements of the group exist as diatomic molecules: F 2, Cl 2,Br2, I2 and At 2
5. Chemical reactions of Group 17 elements:a. With water
i. Solubility (The reactivity of reaction decreases going down Group 17)
ii. Reaction with bromine - shake bromine with water, a brown solution isformed
Br2 + H 2O HBr + HOBriii. Reaction with iodine:
I2+ H 2O HI + HOI
b. With Sodium hydroxide, (NaOH):X2+ 2NaOH → NaX + NaOX + H 2O
I2+ 2NaOH → NaI + NaOI + H 2O
c. With iron (Fe):
2Fe + X 2 → 2FeX 3, X 2 represents any halogen (Cl 2, Br 2 or I 2)
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 13/19
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 14/19
c. i. Element X can react with sodium hydroxide solution. Write the chemicalequation for the reaction.
X2 + 2NaOH → NaX + NaOX + H 2O
ii. Between elements X and Y, which is more electronegative? X is more electronegative than element Y
iii. How does the reactivity of element X and element Y differ? Explain youranswer.- Element X is more reactive than element Y - The size of atom X is smaller than atom Y - The outermost occupied shell of atom X is nearer to the nucleus
compare to atom Y. - The strength of the nucleus of atom X to attract electron into the
outermost shell is stronger than atom Y
Period1. Horizontal rows in the periodic table2. There are seven periods known as period 1, 2, 3, 4, 5, 6, 7.3. The number of period of an element represents the number of shells occupy with
electrons in each atom of element.Elements Proton
NumberElectron Arrangement in
atomNumber of shells in
atomPeriod
Li 3 2.1 2 2 Na 11 2.8.1 3 3 K 19 2.8.8.1 4 4
4. Period 3 elementsElements Na Mg Al Si P S Cl Ar
Proton Number 11 12 13 14 15 16 17 18Electron arrangement 2.8.1 2.8.2 2.8.3 2.8.4 2.8.5 2.8.6 2.8.7 2.8.8 Positive charge in the nucleus +11 +12 +13 +14 +15 +16 +17 +18Radius 0.156 0.136 0.125 0.117 0.110 0.104 0.009 0.001
5. Physical changes across the period 3 (from left to right) a. Atomic radius decreases because:
i. All the atoms of elements have 3 shells occupied with electrons.ii. The proton number increases by one unit from one element to the next
element.iii. Increase in proton number causes the number of positive charge in the
nucleus to increase .iv. The strength of nuclei attraction on the electrons in the shells
increases .v. The atomic radius of elements decreases .
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 15/19
b. Electronegativity increases:i. Electronegativity: The strength of an atom in a molecule to attract
electron towards its nucleus.ii. The atomic radius decreases due to the increasing nuclei attraction on
the valence electron.iii. The strength of nucleus to attract electrons also increases .
c. Physical state:i. The physical state of elements in a period changes from solid to gas
from left to right.ii. Metals on the left are solid while non-metals on the right are usually
gases.
d. Changes in metallic properties and electrical conductivity:
Element Na Mg Al Si P S Cl ArMetallic
propertiesMetal Semi metal Non metal
Electricalconductivity
Good conductorsof electric.
Weak conductor of electricbut it increases with thepresence of boron orphosphorous.Uses: semi-conductor
Cannot conductelectricity
6. Properties of oxide of elements in Period 3:a. Elements in Period 3 can be classified as metals and non-metals based on
basic and acidic properties of their oxides.
Na Mg Al Si P S Cl
Basic oxide Amphoteric oxide Acidic oxide
Metal oxide + water → alkali
Example:Na 2O + H 2O → 2NaOH
Metal oxide + Acid → Salt +
WaterExample:MgO + 2HCl → MgCl 2 + H 2O
Amphoteric oxide react with both acid
and alkali to produce + salt and waterExample:Al2O3 + 6HNO 3 → 2Al(NO 3)3 +3H 2OAl2O3 + 2NaOH → 2NaAlO 2 + H 2O
Non metal oxide + water → acid
Example:SO 2 + H 2O → H 2SO 3
Non metal oxide+ alkali → Salt + WaterExample:SiO 2 + 2NaOH → N 2SiO 3 + H 2O
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 16/19
b. i. Basic oxide is metal oxide that can react with acid to form salt and water .ii. Acidic oxide is non-metal oxide that can react with alkali to form salt and
water iii. Amphoteric oxide is oxide that can react with both acid and alkali to form
salt and water .
c. Complete the following table:i. Reaction with water:
Oxide Solubility in Water pH of theSolution
Type of Oxide
Sodium oxide,Na 2O
White solid dissolve inwater
14 Basicoxide
Magnesium oxide,MgO
White solid slightlydissolve in water
9 Basicoxide
Aluminium oxide,Al 2O3
Insoluble - -
Silicon oxide, SiO 2 Insoluble - -Phosphorousoxide, P 4O10
White solid dissolve inwater
3 Acidicoxide
Sulphur dioxide,SO 2
White solid dissolve inwater
3 Acidicoxide
ii. Reaction between nitric acid and sodium hydroxide solution:
Oxide Observation
Type of Oxide
Reaction withDilute Nitric Acid
Reaction withSodium Hydroxide
SolutionMagnesiumoxide, MgO
The white soliddissolve to formcolourless solution
No change. Thewhite solid does notdissolve
Basic oxide
Aluminiumoxide, Al 2O3
The white soliddissolve to formcolourless solution
The white soliddissolve to formcolourless solution
Amphotericoxide
Silicon oxide,SiO 2
No change. Thewhite solid does notdissolve
The white soliddissolve to formcolourless solution
Acidicoxide
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 17/19
Transition Element
1. Situated between Group 2 and 13. The example of transition element are Sc, Ti, V,Cr, Mn, Fe ,Co , Ni, Cu, and Zn.
2.
Show metal properties:- Shiny, conducts heat and electricity, malleable, high tensil strength, highmelting point and density.
3. Special characteristics:a. Form coloured compound
Example: Iron (III) chloride is brown, Iron (II) chloride is green and copper(II) sulphate is blue.
b. Form different oxidation numbers.c. Form complex ions: MnO 4, Cr 2O7
2-, CrO 42-, etc.
d. Useful as a catalyst in industries.e. Example:
Iron: Haber process in the manufacture of ammonia
N2 + 3H 2 Fe 2NH 3
Vanadium (V) Oxide: Contact process in the manufacture of sulphuric acid
2SO 2 + O 2 2SO 3
Platinum: Ostwald process in the manufacture of nitric acid
EXERCISE
1. The table below shows the number of neutron and relative atomic mass of eightelements represented as P, Q, R, S, T, U and W.
Element P Q R S T U V W
Number of neutron in an atom 12 12 14 14 16 16 18 22
Relative atomic mass 23 24 27 28 31 32 35 40
Number of proton in an atom 11 12 13 14 15 16 17 18
Electron arrangement of an atom 2.8.1 2.8.2 2.8.3 2.8.4 2.8.5 2.8.6 2.8.7 2.8.8
a. i. Complete the above table by writing the number of proton and electron
arrangement for the atom of each element.
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 18/19
8/7/2019 Jadual Berkala Bi
http://slidepdf.com/reader/full/jadual-berkala-bi 19/19
2. Diagram 4 shows part of the Periodic Table of Elements. X, Y, A, B, D, E and F donot represent the actual symbol of the elements.
a. State the position of element B in the Periodic Table.Period 3, Group 13
b. Choose an element that
i. is monoatomic Y ii. forms acidicoxide
D/E iii. has atoms thathave no neutron
X
iv. is an alkali metal A/F v formsamphotericoxide
B vi. has a protonnumber 15
D
vii. is mostelectropositive
F viii. forms basicoxide
A/F ix. forms colouredcompound
G
c. Arrange Y, A, B, D and E according to the order of increasing atomic size.Y, E, D, B, A
d. Compare electronegativity of element D and element E. Explain your answer.- Element E is more electronegative than element D.- Atom E and atom D have same number of shells occupied with
electrons.- The number of proton in the nucleus of atom E is more than atom D.- The strength of nucleus in atom E to attract electron is stronger than
that in atom D