JK-TK/Newdata huggingface dataset:
b) Calculate the relative atomic mass of potassium given that it exist as;
5 93.1% 3919K , 0.01% 4019K , 6.89% 4119K , Working 100 atoms of potassium contains 93.1 atoms of 3919K isotopes 100 atoms of potassium contains 0.01 atoms of 4019K isotopes 100 atoms of potassium contains 6.89 atoms of 4119K isotopes Therefore; RAM of potassium = (93.1/100 x39) + (0.01/100 x 40) +(6.89 /100 x 39) = Note that: Relative atomic mass has no units More atoms of potassium exist as 3919K (93.1%) therefore RAM is nearer to the more abundant 3919K isotope. c) Calculate the relative atomic mass of Neon given that it exist as; 90.92% 2010Ne , 0.26% 2110Ne , 8.82% 2210Ne, Working 100 atoms of Neon contains 90.92 atoms of 2010Ne isotopes 100 atoms of Neon contains 0.26 atoms of 2110Ne isotopes 100 atoms of Neon contains 8.82 atoms of 2210 Ne isotopes Therefore; RAM of Neon = (90.92/100 x20) + (0.26/100 x 21) +(8.82 /100 x 22) = Note that: Relative atomic mass has no units More atoms of Neon exist as 2010Ne (90.92%) therefore RAM is nearer to the more abundant 2010Ne isotope. d) Calculate the relative atomic mass of Argon given that it exist as; 90.92% 2010Ne , 0.26% 2110Ne , 8.82% 2210Ne, NB The relative atomic mass is a measure of the masses of atoms. The higher the relative atomic mass, the heavier the atom. Electrons are found in energy levels/orbital. An energy level is a fixed region around/surrounding the nucleus of an atom occupied by electrons of the same (potential) energy. By convention energy levels are named 1,2,3… outwards from the region nearest to nucleus.
Electrons are found in energy levels/orbital. An energy level is a fixed region around/surrounding the nucleus of an atom occupied by electrons of the same (potential) energy. By convention energy levels are named 1,2,3… outwards from the region nearest to nucleus. Each energy level is occupied by a fixed number of electrons: The 1st energy level is occupied by a maximum of two electrons
6 The 2nd energy level is occupied by a maximum of eight electrons The 3rd energy level is occupied by a maximum of eight electrons( or eighteen electrons if available) The 4th energy level is occupied by a maximum of eight electrons( or eighteen or thirty two electrons if available) This arrangement of electrons in an atom is called electron configuration / structure.
Scientists have tried to group them together in a periodic table. A periodic table is a horizontal and vertical arrangement of elements according to their atomic numbers. This table was successfully arranged in 1913 by the British scientist Henry Moseley from the previous work of the Russian Scientist Dmitri Mendeleev. The horizontal arrangement forms period. Atoms in the same period have the same the same number of energy levels in their electronic structure. i.e. The number of energy levels in the electronic configuration of an element determine the period to which the element is in the periodic table. e.g. Which period of the periodic table are the following isotopes/elements/atoms? a) 126C Electron structure 2:4 => 2 energy levels used thus Period 2 b) 2311Na Electron structure 2:8:1 => 3 energy levels used thus Period 3 c) 3919K Electron structure 2:8:8:1 => 4 energy levels used thus Period 4 d) 11H Electron structure 1: => 1 energy level used thus Period 1 The vertical arrangement of elements forms a group. Atoms in the same have the same the same group have the same number of outer energy level electrons as per their electronic structure. i.e. The number of electrons in the outer energy level an element determine the group to which the element is ,in the periodic table. 13 a) 126C Electron structure 2:4 => 4 electrons in outer energy level thus Group IV b) 2311C Electron structure 2:8:1 => 1 electron in outer energy level thus Group I c) 3919K Electron structure 2:8:8:1=>1 electron in outer energy level thus Group I d) 11H Electron structure 1: => 1 electron in outer energy level thus Group I By convention; (i)Periods are named using English numerals 1,2,3,4,… (ii)Groups are named using Roman numerals I,II,III,IV,… There are eighteen groups in a standard periodic table. There are seven periods in a standard periodic table. When an atom has maximum number of electrons in its outer energy level, it is said to be stable. When an atom has no maximum number of electrons in its outer energy level, it is said to be unstable. All stable atoms are in group 8/18 of the periodic table. All other elements are unstable.
When an atom has no maximum number of electrons in its outer energy level, it is said to be unstable. All stable atoms are in group 8/18 of the periodic table. All other elements are unstable. THE STANDARD PERIODIC TABLE OF ELEMENTS
14 All unstable atoms/isotopes try to be stable through chemical reactions. A chemical reaction involves gaining or losing outer electrons (electron transfer) .When electron transfer take place, an ion is formed. An ion is formed when an unstable atom gain or donate electrons in its outer energy level inorder to be stable. Whether an atom gain or donate electrons depend on the relative energy required to donate or gain extra electrons i.e. Examples 1. 199 F has electronic structure/configuration 2:7. It can donate the seven outer electrons to have stable electronic structure/configuration 2:. It can gain one extra electron to have stable electronic structure/configuration 2:8. Gaining requires less energy, and thus Fluorine reacts by gaining one extra electrons. 2. 2313 Al has electronic structure/configuration 2:8:3 It can donate the three outer electrons to have stable electronic structure/configuration 2:8. It can gain five extra electrons to have stable electronic structure/configuration 2:8:8. Donating requires less energy, and thus Aluminium reacts by donating its three outer electrons. Elements with less than four electrons in the outer energy level donates /lose the outer electrons to be stable and form a positively charged ion called cation. A cation therefore has more protons(positive charge) than electrons(negative charge) Generally metals usually form cation Elements with more than four electrons in the outer energy level gain /acquire extra electrons in the outer energy level to be stable and form a negatively charged ion called anion. An anion therefore has less protons(positive charge) than electrons(negative charge) Generally non metals usually form anion. Except Hydrogen The charge carried by an ion is equal to the number of electrons gained/acquired or donated/lost. Examples of ion formation 1.11H H -> H+ + e (atom) (monovalent cation) (electrons donated/lost) Electronic configuration 1: (No electrons remains)
15 2. 2713 Al Al -> Al3+ + 3e (atom) (trivalent cation) (3 electrons donated/lost) Electron 2:8:3 2:8 structure (unstable) (stable) 3.
Except Hydrogen The charge carried by an ion is equal to the number of electrons gained/acquired or donated/lost. Examples of ion formation 1.11H H -> H+ + e (atom) (monovalent cation) (electrons donated/lost) Electronic configuration 1: (No electrons remains)
15 2. 2713 Al Al -> Al3+ + 3e (atom) (trivalent cation) (3 electrons donated/lost) Electron 2:8:3 2:8 structure (unstable) (stable) 3. 2311 Na Na -> Na+ + e (atom) (cation) ( 1 electrons donated/lost) Electron 2:8:1 2:8 structure (unstable) (stable) 4. 2412Mg Mg -> Mg2+ + 2e (atom) (cation) ( 2 electrons donated/lost) Electron 2:8:1 2:8 structure (unstable) (stable) 5. 168O O + 2e -> O2- (atom) ( 2 electrons gained/acquired) (anion) Electron 2:6 2:8 structure (unstable) (stable) 6. 147N N + 3e -> N3- (atom) ( 3 electrons gained/acquired) (anion) Electron 2:5 2:8 structure (unstable) (stable) 7. 3115P P + 3e -> P3- (atom) ( 3 electrons gained/acquired) (anion) Electron 2:5 2:8 structure (unstable) (stable) 8. 199F F + e -> F- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:7 2:8 structure (unstable) (stable) 9. 3517Cl
16 Cl + e -> Cl- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:8:7 2:8:8 structure (unstable) (stable) 3. 3919 K K -> K+ + e (atom) (cation) ( 1 electrons donated/lost) Electron 2:8:8:1 2:8:8 structure (unstable) (stable) When an element donate/loses its outer electrons ,the process is called oxidation.
199F F + e -> F- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:7 2:8 structure (unstable) (stable) 9. 3517Cl
16 Cl + e -> Cl- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:8:7 2:8:8 structure (unstable) (stable) 3. 3919 K K -> K+ + e (atom) (cation) ( 1 electrons donated/lost) Electron 2:8:8:1 2:8:8 structure (unstable) (stable) When an element donate/loses its outer electrons ,the process is called oxidation. When an element acquires/gains extra electrons in its outer energy level,the process is called reduction.The charge carried by an atom, cation or anion is its oxidation state. Table showing the oxidation states of some isotopes Element Symbol of element / isotopes Charge of ion Oxidation state Hydrogen 1H(deuterium) 31H(Tritium) H+ H+ H+ +1 +1 +1 Chlorine 17Cl Cl- Cl- -1 -1 Potassium 19K 4119K K+ K+ K+ +1 +1 +1 Oxygen 8O O2- O2- -2 -2 Magnesium 2412Mg Mg2+ +2 sodium 2311Na Na+ +1 Copper Cu Cu+ Cu2+ +1 +2 Iron Fe2+ Fe3+ +2 +3 Lead Pb2+ Pb4+ +2 +4
17 Manganese Mn2+ Mn7+ +2 +7 Chromium Cr3+ Cr6+ +3 +6 Sulphur S4+ S6+ +4 +6 Carbon C2+ C4+ +2 +4 Note : Some elements can exist in more than one oxidation state.They are said to have variable oxidation state. Roman capital numeral is used to indicate the oxidation state of an element with a variable oxidation state in a compound.
When an element acquires/gains extra electrons in its outer energy level,the process is called reduction.The charge carried by an atom, cation or anion is its oxidation state. Table showing the oxidation states of some isotopes Element Symbol of element / isotopes Charge of ion Oxidation state Hydrogen 1H(deuterium) 31H(Tritium) H+ H+ H+ +1 +1 +1 Chlorine 17Cl Cl- Cl- -1 -1 Potassium 19K 4119K K+ K+ K+ +1 +1 +1 Oxygen 8O O2- O2- -2 -2 Magnesium 2412Mg Mg2+ +2 sodium 2311Na Na+ +1 Copper Cu Cu+ Cu2+ +1 +2 Iron Fe2+ Fe3+ +2 +3 Lead Pb2+ Pb4+ +2 +4
17 Manganese Mn2+ Mn7+ +2 +7 Chromium Cr3+ Cr6+ +3 +6 Sulphur S4+ S6+ +4 +6 Carbon C2+ C4+ +2 +4 Note : Some elements can exist in more than one oxidation state.They are said to have variable oxidation state. Roman capital numeral is used to indicate the oxidation state of an element with a variable oxidation state in a compound. Examples: (i) Copper (I) means Cu+ as in Copper(I)oxide (ii) Copper (II) means Cu2+ as in Copper(II)oxide (iii) Iron (II) means Fe2+ as in Iron(II)sulphide (iv) Iron (III) means Fe3+ as in Iron(III)chloride (iv) Sulphur(VI)mean S6+ as in Iron(III)sulphate(VI) (v) Sulphur(VI)mean S6+ as in sulphur(VI)oxide (vi) Sulphur(IV)mean S4+ as in sulphur(IV)oxide (vii) Sulphur(IV)mean S4+ as in sodium sulphate(IV) (ix) Carbon(IV)mean C4+ as in carbon(IV)oxide (x) Carbon(IV)mean C4+ as in Lead(II)carbonate(IV) (xi) Carbon(II)mean C2+ as in carbon(II)oxide (xii) Manganese(IV)mean Mn4+ as in Manganese(IV)oxide A compound is a combination of two or more elements in fixed proportions.
Table showing the oxidation states of some isotopes Element Symbol of element / isotopes Charge of ion Oxidation state Hydrogen 1H(deuterium) 31H(Tritium) H+ H+ H+ +1 +1 +1 Chlorine 17Cl Cl- Cl- -1 -1 Potassium 19K 4119K K+ K+ K+ +1 +1 +1 Oxygen 8O O2- O2- -2 -2 Magnesium 2412Mg Mg2+ +2 sodium 2311Na Na+ +1 Copper Cu Cu+ Cu2+ +1 +2 Iron Fe2+ Fe3+ +2 +3 Lead Pb2+ Pb4+ +2 +4
17 Manganese Mn2+ Mn7+ +2 +7 Chromium Cr3+ Cr6+ +3 +6 Sulphur S4+ S6+ +4 +6 Carbon C2+ C4+ +2 +4 Note : Some elements can exist in more than one oxidation state.They are said to have variable oxidation state. Roman capital numeral is used to indicate the oxidation state of an element with a variable oxidation state in a compound. Examples: (i) Copper (I) means Cu+ as in Copper(I)oxide (ii) Copper (II) means Cu2+ as in Copper(II)oxide (iii) Iron (II) means Fe2+ as in Iron(II)sulphide (iv) Iron (III) means Fe3+ as in Iron(III)chloride (iv) Sulphur(VI)mean S6+ as in Iron(III)sulphate(VI) (v) Sulphur(VI)mean S6+ as in sulphur(VI)oxide (vi) Sulphur(IV)mean S4+ as in sulphur(IV)oxide (vii) Sulphur(IV)mean S4+ as in sodium sulphate(IV) (ix) Carbon(IV)mean C4+ as in carbon(IV)oxide (x) Carbon(IV)mean C4+ as in Lead(II)carbonate(IV) (xi) Carbon(II)mean C2+ as in carbon(II)oxide (xii) Manganese(IV)mean Mn4+ as in Manganese(IV)oxide A compound is a combination of two or more elements in fixed proportions. The ratio of the atoms making a compound is called the chemical formulae.
Roman capital numeral is used to indicate the oxidation state of an element with a variable oxidation state in a compound. Examples: (i) Copper (I) means Cu+ as in Copper(I)oxide (ii) Copper (II) means Cu2+ as in Copper(II)oxide (iii) Iron (II) means Fe2+ as in Iron(II)sulphide (iv) Iron (III) means Fe3+ as in Iron(III)chloride (iv) Sulphur(VI)mean S6+ as in Iron(III)sulphate(VI) (v) Sulphur(VI)mean S6+ as in sulphur(VI)oxide (vi) Sulphur(IV)mean S4+ as in sulphur(IV)oxide (vii) Sulphur(IV)mean S4+ as in sodium sulphate(IV) (ix) Carbon(IV)mean C4+ as in carbon(IV)oxide (x) Carbon(IV)mean C4+ as in Lead(II)carbonate(IV) (xi) Carbon(II)mean C2+ as in carbon(II)oxide (xii) Manganese(IV)mean Mn4+ as in Manganese(IV)oxide A compound is a combination of two or more elements in fixed proportions. The ratio of the atoms making a compound is called the chemical formulae. Elements combine together to form a compound depending on their combining power. The combining power of atoms in an element is called Valency.Valency of an element is equal to the number of: (i)hydrogen atoms that an atom of element can combine with or displace. (ii)electrons gained /acquired in outer energy level by non metals to be stable/attain duplet/octet. (iii)electrons donated/lost by outer energy level of metals to be stable/attain octet/duplet. (iv)charges carried by ions/cations/ions
18 Group of atoms that react as a unit during chemical reactions are called radicals.Elements with variable oxidation state also have more than one valency. Table showing the valency of common radicals.
(iii)electrons donated/lost by outer energy level of metals to be stable/attain octet/duplet. (iv)charges carried by ions/cations/ions
18 Group of atoms that react as a unit during chemical reactions are called radicals.Elements with variable oxidation state also have more than one valency. Table showing the valency of common radicals. Radical name Chemical formulae Combining power / Valency Ammonium NH4 + 1 Hydroxide OH- 1 Nitrate(V) NO3 - 1 Hydrogen carbonate HCO3- 1 Hydrogen sulphate(VI) HSO4- 1 Hydrogen sulphate(IV) HSO3- 1 Manganate(VII) MnO4- 1 Chromate(VI) CrO42- 2 Dichromate(VI) Cr2O72- 2 Sulphate(VI) SO42- 2 Sulphate(IV) SO32- 2 Carbonate(IV) CO32- 2 Phosphate(V) PO42- 3 Table showing the valency of some common metal and non metals Element/metal Valency Element/non metal Valency Hydrogen 1 Florine 1 Lithium 1 Chlorine 1 Beryllium 2 Bromine 1 Boron 3 Iodine 1 Sodium 1 Carbon 4 Magnesium 2 Nitrogen 3 Aluminium 3 Oxygen 2 Potassium 1 Phosphorus 3 Calcium 2 Zinc 2 Barium 2 Mercury 2 Iron 2 and 3 Copper 1 and 2 Manganese 2 and 4 Lead 2 and 4
19 From the valency of elements , the chemical formular of a compound can be derived using the following procedure: (i)Identify the elements and radicals making the compound (ii)Write the symbol/formular of the elements making the compound starting with the metallic element (iii)Assign the valency of each element /radical as superscript. (iv)Interchange/exchange the valencies of each element as subscript. (v)Divide by the smallest/lowest valency to derive the smallest whole number ratios Ignore a valency of 1. This is the chemical formula.
(iv)Interchange/exchange the valencies of each element as subscript. (v)Divide by the smallest/lowest valency to derive the smallest whole number ratios Ignore a valency of 1. This is the chemical formula. Practice examples Write the chemical formula of (a)Aluminium oxide Elements making compound Aluminium Oxygen Symbol of elements/radicals in compound Al O Assign valencies as superscript Al3 O2 Exchange/Interchange the valencies as subscript Al2 O3 Divide by smallest valency to get whole number - - Chemical formula of Aluminium oxide is thus: Al2 O3 This means:2atoms of Aluminium combine with 3 atoms of Oxygen (b)Sodium oxide Elements making compound Sodium Oxygen Symbol of elements/radicals in compound Na O Assign valencies as superscript Na1 O2 Exchange/Interchange the valencies as subscript Na2 O1 Divide by smallest valency to get whole number - - Chemical formula of Sodium oxide is thus: Na2 O This means:2atoms of Sodium combine with 1 atom of Oxygen (c)Calcium oxide Elements making compound Calcium Oxygen Symbol of elements/radicals in compound Ca O Assign valencies as superscript Ca2 O2 Exchange/Interchange the valencies as subscript Ca2 O2 Divide by two to get smallest whole number ratio Ca1 O1
20 Chemical formula of Calcium oxide is thus: CaO This means:1 atom of calcium combine with 1 atom of Oxygen. (d)Lead(IV)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb4 O2 Exchange/Interchange the valencies as subscript Pb2 O4 Divide by two to get smallest whole number ratio Pb1 O2 Chemical formula of Lead(IV) oxide is thus: PbO2 This means:1 atom of lead combine with 2 atoms of Oxygen. (e)Lead(II)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb2 O2 Exchange/Interchange the valencies as subscript Pb2 O2 Divide by two to get smallest whole number ratio Pb1 O1 Chemical formula of Lead(II) oxide is thus: PbO This means:1 atom of lead combine with 1 atom of Oxygen.
Practice examples Write the chemical formula of (a)Aluminium oxide Elements making compound Aluminium Oxygen Symbol of elements/radicals in compound Al O Assign valencies as superscript Al3 O2 Exchange/Interchange the valencies as subscript Al2 O3 Divide by smallest valency to get whole number - - Chemical formula of Aluminium oxide is thus: Al2 O3 This means:2atoms of Aluminium combine with 3 atoms of Oxygen (b)Sodium oxide Elements making compound Sodium Oxygen Symbol of elements/radicals in compound Na O Assign valencies as superscript Na1 O2 Exchange/Interchange the valencies as subscript Na2 O1 Divide by smallest valency to get whole number - - Chemical formula of Sodium oxide is thus: Na2 O This means:2atoms of Sodium combine with 1 atom of Oxygen (c)Calcium oxide Elements making compound Calcium Oxygen Symbol of elements/radicals in compound Ca O Assign valencies as superscript Ca2 O2 Exchange/Interchange the valencies as subscript Ca2 O2 Divide by two to get smallest whole number ratio Ca1 O1
20 Chemical formula of Calcium oxide is thus: CaO This means:1 atom of calcium combine with 1 atom of Oxygen. (d)Lead(IV)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb4 O2 Exchange/Interchange the valencies as subscript Pb2 O4 Divide by two to get smallest whole number ratio Pb1 O2 Chemical formula of Lead(IV) oxide is thus: PbO2 This means:1 atom of lead combine with 2 atoms of Oxygen. (e)Lead(II)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb2 O2 Exchange/Interchange the valencies as subscript Pb2 O2 Divide by two to get smallest whole number ratio Pb1 O1 Chemical formula of Lead(II) oxide is thus: PbO This means:1 atom of lead combine with 1 atom of Oxygen. (e)Iron(III)oxide Elements making compound Iron Oxygen Symbol of elements/radicals in compound Fe O Assign valencies as superscript Fe3 O2 Exchange/Interchange the valencies as subscript Fe2 O3 Divide by two to get smallest whole number ratio - - Chemical formula of Iron(III) oxide is thus: Fe2O3 This means:2 atom of lead combine with 3 atom of Oxygen.
(d)Lead(IV)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb4 O2 Exchange/Interchange the valencies as subscript Pb2 O4 Divide by two to get smallest whole number ratio Pb1 O2 Chemical formula of Lead(IV) oxide is thus: PbO2 This means:1 atom of lead combine with 2 atoms of Oxygen. (e)Lead(II)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb2 O2 Exchange/Interchange the valencies as subscript Pb2 O2 Divide by two to get smallest whole number ratio Pb1 O1 Chemical formula of Lead(II) oxide is thus: PbO This means:1 atom of lead combine with 1 atom of Oxygen. (e)Iron(III)oxide Elements making compound Iron Oxygen Symbol of elements/radicals in compound Fe O Assign valencies as superscript Fe3 O2 Exchange/Interchange the valencies as subscript Fe2 O3 Divide by two to get smallest whole number ratio - - Chemical formula of Iron(III) oxide is thus: Fe2O3 This means:2 atom of lead combine with 3 atom of Oxygen. (f)Iron(II)sulphate(VI) Elements making compound Iron sulphate(VI) Symbol of elements/radicals in compound Fe SO4 Assign valencies as superscript Fe2 SO4 2 Exchange/Interchange the valencies as subscript Fe2 SO4 2 Divide by two to get smallest whole number ratio Fe1 SO4 1
21 Chemical formula of Iron(II) sulphate(VI) is thus: FeSO4 This means:1 atom of Iron combine with 1 sulphate(VI) radical. (g)Copper(II)sulphate(VI) Elements making compound Copper sulphate(VI) Symbol of elements/radicals in compound Cu SO4 Assign valencies as superscript Cu2 SO4 2 Exchange/Interchange the valencies as subscript Cu2 SO4 2 Divide by two to get smallest whole number ratio Cu1 SO4 1 Chemical formula of Cu(II)sulphate(VI) is thus: CuSO4 This means:1 atom of Copper combine with 1 sulphate(VI) radical.
(e)Iron(III)oxide Elements making compound Iron Oxygen Symbol of elements/radicals in compound Fe O Assign valencies as superscript Fe3 O2 Exchange/Interchange the valencies as subscript Fe2 O3 Divide by two to get smallest whole number ratio - - Chemical formula of Iron(III) oxide is thus: Fe2O3 This means:2 atom of lead combine with 3 atom of Oxygen. (f)Iron(II)sulphate(VI) Elements making compound Iron sulphate(VI) Symbol of elements/radicals in compound Fe SO4 Assign valencies as superscript Fe2 SO4 2 Exchange/Interchange the valencies as subscript Fe2 SO4 2 Divide by two to get smallest whole number ratio Fe1 SO4 1
21 Chemical formula of Iron(II) sulphate(VI) is thus: FeSO4 This means:1 atom of Iron combine with 1 sulphate(VI) radical. (g)Copper(II)sulphate(VI) Elements making compound Copper sulphate(VI) Symbol of elements/radicals in compound Cu SO4 Assign valencies as superscript Cu2 SO4 2 Exchange/Interchange the valencies as subscript Cu2 SO4 2 Divide by two to get smallest whole number ratio Cu1 SO4 1 Chemical formula of Cu(II)sulphate(VI) is thus: CuSO4 This means:1 atom of Copper combine with 1 sulphate(VI) radical. (h)Aluminium sulphate(VI) Elements making compound Aluminium sulphate(VI) Symbol of elements/radicals in compound Al SO4 Assign valencies as superscript Al3 SO4 2 Exchange/Interchange the valencies as subscript Al2 SO4 3 Divide by two to get smallest whole number ratio - - Chemical formula of Aluminium sulphate(VI) is thus: Al2(SO4)3 This means:2 atom of Aluminium combine with 3 sulphate(VI) radical.