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CHEMISTRY[FORM 4 CHAPTER 1:PERIODIC TABLE OF ELEMENT]

NAME: CLASS: PREPARED BY: MR.IWIN

4.1 Periodic Table

o Elements in the Periodic Table are arranged according to theirproton number.o Horizontal rows are called periods.o Vertical columns are called groups.

4.2 Groups in the Periodic Tableo Specific name of groups:

Group 1 : Alkali metals Group 2 : Alkali earth metals Group 3 12 : Transition elements Group 17 : Halogens Group 18 : Noble gases

o Type of substances :Group Type of substances

1,2 and 13 metals3 to 12 ( transition elements ) metals

14, 15, 16, 17, 18 non-metals

4.3 To determine the position of elements in the Periodic Table

1. Write the electron arrangement of the element.2. The number of valence electrons group3. The number of shells period

Example :Sodium element has a proton number of 11

The electron arrangement of a sodium atom = 2.8.1

4.4 Group 18 ( He, Ne, Ar, Kr, Xe, Rn )

o Changes of physical properties when going down group 18( Noble gas).

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Properties Changes Explanations

Atomic size increases Because the number of occupied shells increases.Melting &

boiling Pointincrease Because

i. the atomic size increases when going down the group.ii. The force of attraction between particles become stronger.

iii. Thus, more heat is needed to overcome the stronger force.

1 valence electron meansthat sodium is in Group 1.

3 shells means thatsodium is in Period 3.

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o the gases in group 18 are inert chemically or chemically unreactive and exist asmonoatomic gases because they have stable electron arrangement.

o The uses of noble gases.Gas uses

Helium To fill weather balloons.Neon To fill neon light to light up advertisement boards.Argon To fill electrical bulbs.

4.5 Group 1 ( Li, Na, K, Rb, Cs, Fr )o Physical properties:

Conduct electricity and heat Softer, low melting/ boiling point and less dense compared to other metals.

o Changes of properties when going down group 1( Alkali metals).

o Chemical properties

X = metals in group 1( Li, Na, K, Rb, Cs, Fr )

4.6 Group 17 ( F, Cl, Br, I, At )

o Physical properties ;

Very low melting and boiling point Pungent smell and are poisonous Exist as diatomic molecules at room temperature (F2, Cl2, Br2, I2, At2)

o Changes of properties when going down group 17( Halogens).

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Properties Changes Explanations

Atomic size increases Because the number of occupied shells increases.Melting & boilingPoint

decrease Becausei. the atomic size increases when going down the group.ii. The metal bond between atoms become weaker.iii. Thus, less heat is needed to overcome the weaker bond.

Reactivity(Electropositivitystrength to releaseelectron)

increases Becausei. The atomic size/radius increases when going down the group.ii. The valence electron in the outermost shell becomes further from the

nucleus.iii. The force of attraction of nucleus on the valance electron become weaker.iv. The valence electron becomes easier to be released.

Chemical properties Chemical equations

Reacts with water to produce alkaline metal hydroxidesolutions and hydrogen gas.

2 X + 2 H2O 2 XOH + H2

Burns in oxygen gas to produce white solid metal oxides. 4 X + O2

2 X2OBurns in chlorine gas to form white solid metal chloride. 2 X + Cl2 2 XCl

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o Chemical properties

X = halogen ( F, Cl, Br, I, At)

4.7 Period 3 ( Na, Mg, Al, Si, P, S, Cl, Ar )o Changes of properties across Period 3.

o Changes in oxide properties across Period 3 from left to right.Basic oxide amphoteric oxide acidic oxide

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Properties Changes Explanations

Atomic size increases Because the number of occupied shells increases.Melting & boilingPoint

increases Becausei. the atomic size increases when going down the group.ii. The force of attraction between particles become stronger.iii. Thus, more heat is needed to overcome the stronger force.

Reactivity(Electronegativity

strength toattract electron)

decreases Becausei. The atomic size/radius increases when going down the group.

ii. The outermost shell becomes further from the nucleus.iii. The strength to attract one electron into the outermost shell by the nucleusbecomes weaker.

iv. The tendency to receive an electron decrease.

Chemical properties Chemical equations

Reacts with water to produce two acids X2 + H2O HX + HOXReacts with hot iron to form a brown solid, iron (III)halides

3 X2 + 2 Fe 2 FeX3

Reacts with sodium hydroxide solution, NaOH to formsodium halide, sodium halite (I) and water.

X2 + 2NaOH NaX + NaOX + H2O

Properties Changes Explanations

Atomic size decreases Because across Period 3i. All the atoms of elements have 3 shells occupied with electrons.ii. Proton number increases by one unit from one element to the next element

causes the positive charge of the nucleus to increase.iii. Nuclei attraction on the electrons of the first 3 shells increases causes the

atomic size to decrease.

Electronegativity(strength to attract

electron)

increases Because across Period 3i. The atomic size/radius decreases while the positive charge of the nucleus

increases.ii. The strength of atom to attract electrons also increases.

Element Sodium Magnesiu

m

Aluminiu

m

Silicon Phosphoru

s

Sulphur Chlorin

e

Acid-baseproperties ofelement oxide

Base Base amphoteric acid acid acid acid

Reaction withacidic or

alkalinesolution

acid

X alkali

acid

X alkali

acid

alkali

X acid

alkali

X acid

alkali

X acid

alkali

X acid

alkali

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= soluble

4.8 Transition Elments / metals (Group 3 Group 12)

o 4 special characteristics of transition elements: Form ions which have different oxidation numbers.

Form coloured ions / compounds. Form complex ions. Act as catalysts in certain reactions.

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X = insoluble