revision on chapter periodic table, chemical bonding and electrolysis with answers
description
Transcript of revision on chapter periodic table, chemical bonding and electrolysis with answers
PERIODIC TABLEa. i.Label group
1
17
Transition metal
13 14 15 16
182
ii.Label period 1 to 5
Period 1
Period 2
Period 3
Period 4
Period 5
1
2
Transition metal
13 14 15 16 17
18
iii.Place proton number of elements 1 to 20 in the periodic table above
1 2
3 4 5 6 7 8 9 10
11
12 13 14 15 16 17 18
19 20
iv.Place all the elements given in the periodic table above with their
symbols
Transition metal
H He
F Ne
Na
Cu
Cl
Br
Ar
K Mn
Li
b)Why are all noble gases chemically not reactive?
• Because they have stable electron arrangement with octet or duplet structure.
• So they do not release, Gain or share electron
c.State 3 physical properties of element sodium
1.Soft metals (easily cut with a razor blade)
2.Low melting and boiling point compare to other metals
3.Low density
4.Good conductor of heat and electricity
Sodium undergoes the following reactions. Write chemical equation:
i) With oxygen:
ii) With water:
iii) With chlorine:
4Na + O2 2Na2O
2Na + 2H2O 2NaOH + H2
2Na + Cl2 2NaCl
The reaction of Potassium with water is more vigorous than the reaction of sodium with water. Explain
• Because potassium atom is bigger than sodium atom ,
• So the distance between nucleus and valence electron in potassium atom is further than sodium atom
• nuclei attraction in potassium is weaker, therefore easier to release electron
• Potassium is more reactive than sodium
State 3 physical properties of element Chlorine:
• Yellow gas at room temperature
• Turn moist blue litmus paper to red and decolourised
• Very soluble in water
g. Chlorine undergoes reaction with heated iron wool.
Write chemical equation
2Fe + 3Cl2 2FeCl3
or
Fe + Cl2 FeCl2
The reaction of chlorine with heated iron is more vigorous than the reaction of bromine with heated iron . Explain• Chlorine atom is smaller than bromine
atom • The distance between nucleus and
valence electron in Chlorine atom is shorter than bromine atom
• Causing the nuclei attraction to be stronger in chlorine atom
• Thus, chlorine atom is easier to attract electron causing it to be more reactive
State 3 special properties of transition elements compared to other elements
• Form coloured ion and compound
• Have many oxidation number• Act as catalyst• Form complex ion
When going across a period from left to right, the atoms get smaller in size. Explain• as the proton number increase, the
positively charged also increase• Thus, the nuclei attraction also
increase• The electron are pulled closer to the
nucleus causing the size to be smaller
“Sesiapa yang hendak mengetahui
kedudukannya di sisi Allah
maka lihatlah kedudukan Allah di dalam hatinya.
Sesungguhnya Allah SWT meletakkan kedudukan
hambanya di sisiNya sebagaimana hamba meletakkanNya
di dalam dirinya.”THE END TOPIC 4
CHEMICAL BONDS
REVISION
a) Sodium and oxygen ( given proton no. Na, 11: O, 8)
Step 1) determine whether ionic or covalent?
Step 3) Arrange the atoms
Step 4) Draw electron arrangement
Step 2) write formula- so you know how many atoms involve
ionic
Na2O
Na O Na
See next slide
Draw electron arrangement for compounds formed betweena) Sodium and oxygen ( given proton no. Na, 11: O, 8)
a) water ( given proton no. H, 1: O, 8)
Step 1) determine whether ionic or covalent?
Step 3) Arrange the atoms
Step 4) Draw electron arrangement
Step 2) write formula- so you know how many atoms involve
covalent
H2O
H O H
See next slide
b) For water molecule
a) Carbon and chlorine ( given proton no. C, 6: Cl, 17)
Step 1) determine whether ionic or covalent?
Step 3) Arrange the atoms
Step 4) Draw electron arrangement
Step 2) write formula- so you know how many atoms involve
covalent
CCl4
See next slide
c) Carbon and chlorine
State 3 physical properties of sodium oxide
• Solid at room temperature• Soluble in water• Insoluble in organic solvent• Conduct electricity in molten
and aqueous state• High melting point and boiling
point
State 3 physical properties of water
• Does not conduct electricity in in any state
• Low melting point and boiling point
• Colourless liquid at room temperature
1. MOLTEN LEAD(II)IODIDE WITH CARBON ELECTRODE
1)Electrolysis of molten PbI2 using carbon as electrode
a)Ions present :
Anode(+) Cathode(-)b)Ion attracted c) Ion discharged
Pb2+ , I-
I- Pb2+
I- Pb2+
d) Half equation :ANODE : CATHODE :
e) Product :
• ANODE :
• CATHODE :
2I- I2+2ePb2+ +2e Pb
Iodine gas
Lead metal
ANODE CATHODE
OBSER A PURPLE GAS EVOLVED
GREY AND SHINY SOLID DEPOSITED
2. HYDROCHLORIC ACID 0.0001 moldm-3 WITH CARBON ELECTRODE
ALL IONS PRESENT
H+ , Cl- & OH-
2)Electrolysis of HCl, 0.0001 moldm-3 using carbon as electrode
a)Ion present :
Anode Cathodeb)Ion attracted c) Ion discharged
H+ , Cl- , OH-
Cl- , OH- H+
OH-H+
d) Half equation :ANODE : CATHODE :
e) Product :
• ANODE :
• CATHODE :
4OH- O2+ 2H2O +4e
2H+ +2e H2
Oxygen and water
Hydrogen gas
ANODE CATHODEOBS COLOURLESS
GAS THAT REKINDLES GLOWING WOODEN SPLINTER
COLOURLESS GAS THAT GIVES ‘POP’ SOUND -TESTED USING BURNING WOODEN SPLINTER
2)Electrolysis of CuSO4, 1.0 moldm-3 using carbon as electrode
a)Ions present :
Anode Cathodeb)Ion attracted c) Ion discharged
Cu2+ , SO42- ,H+, OH-
SO42- , OH- Cu2+ , H+
OH- Cu2+
d) Half equation :ANODE : CATHODE :
e) Product :
• ANODE :
• CATHODE :
4OH- O2+ 2H2O +4e
Cu2+ +2e Cu
Oxygen and water
Copper metal
2)Electrolysis of CuSO4, 1.0 moldm-3 using copper as electrode
a)Ions present:
Anode Cathodeb)Ion attracted c) Ion discharged
Cu2+ , SO42- ,H+, OH-
SO42- , OH- Cu2+ , H+
Cu2+No ions are discharged
d) Half equation :ANODE : CATHODE :
e) Product :
• ANODE :
• CATHODE :
Cu Cu2+ +2e
Cu2+ +2e Cu
Copper(II) ions
Copper metal