JK-TK/Newdata huggingface dataset:
A​ ​piece​ ​of​ ​phosphorous​ ​was​ ​burnt​ ​in​ ​excess​ ​air.​ ​The​ ​product​ ​obtained​ ​was​ ​shaken​ ​with​ ​a small ​ ​amount​ ​of​ ​hot​ ​water​ ​to​ ​make​ ​a​ ​solution ​ ​ ​ ​ ​i)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​burning​ ​of​ ​phosphorus​ ​in​ ​excess​ ​air ​ ​ ​ ​ ​ii)​ ​The​ ​solution​ ​obtained​ ​in​ ​(b)​ ​above​ ​as​ ​found​ ​to​ ​have​ ​pH​ ​of​ ​2.​ ​ ​Give​ ​reasons​ ​for​ ​this ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​observation 16. Study​ ​the​ ​set-up​ ​below​ ​and​ ​answer​ ​the​ ​questions​ ​that​ ​follow:- (a)​ ​State​ ​two​ ​observations​ ​that​ ​would​ ​be​ ​made​ ​after​ ​one​ ​week.​ ​Explain (b)​ ​Write​ ​the​ ​equation​ ​of​ ​the​ ​reaction​ ​taking​ ​place​ ​in​ ​the​ ​test-tube 17. Fe​3​O​4​​ ​and​ ​FeO​ ​are​ ​oxides​ ​of​ ​iron​ ​which​ ​can​ ​be​ ​produced​ ​in​ ​the​ ​laboratory (a)​ ​Write​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​which​ ​can​ ​be​ ​used​ ​to​ ​produce​ ​each​ ​of​ ​the oxides (b)​ ​Wire​ ​an​ ​ionic​ ​equation​ ​for​ ​the​ ​reaction​ ​between​ ​the​ ​oxide,​ ​Fe​3​O​4​​ ​and​ ​a​ ​dilute​ ​acid. 18.Below​ ​is​ ​a​ ​list​ ​of​ ​oxides.
Study​ ​the​ ​set-up​ ​below​ ​and​ ​answer​ ​the​ ​questions​ ​that​ ​follow:- (a)​ ​State​ ​two​ ​observations​ ​that​ ​would​ ​be​ ​made​ ​after​ ​one​ ​week.​ ​Explain (b)​ ​Write​ ​the​ ​equation​ ​of​ ​the​ ​reaction​ ​taking​ ​place​ ​in​ ​the​ ​test-tube 17. Fe​3​O​4​​ ​and​ ​FeO​ ​are​ ​oxides​ ​of​ ​iron​ ​which​ ​can​ ​be​ ​produced​ ​in​ ​the​ ​laboratory (a)​ ​Write​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​which​ ​can​ ​be​ ​used​ ​to​ ​produce​ ​each​ ​of​ ​the oxides (b)​ ​Wire​ ​an​ ​ionic​ ​equation​ ​for​ ​the​ ​reaction​ ​between​ ​the​ ​oxide,​ ​Fe​3​O​4​​ ​and​ ​a​ ​dilute​ ​acid. 18.Below​ ​is​ ​a​ ​list​ ​of​ ​oxides. MgO,​ ​N​2​O​,​ ​K​2​O,​ ​CaO​ ​ans​ ​Al​2​O​3 Select:- a)​ ​A​ ​neutral​ ​oxide. b)​ ​A​ ​highly​ ​water​ ​soluble​ ​basic​ ​oxide. c)​ ​An​ ​oxide​ ​which​ ​can​ ​react​ ​with​ ​both​ ​sodium​ ​hydroxide​ ​solution​ ​and​ ​dilute​ ​hydrochloric acid. 19.
b)​ ​A​ ​highly​ ​water​ ​soluble​ ​basic​ ​oxide. c)​ ​An​ ​oxide​ ​which​ ​can​ ​react​ ​with​ ​both​ ​sodium​ ​hydroxide​ ​solution​ ​and​ ​dilute​ ​hydrochloric acid. 19. The​ ​diagram​ ​below​ ​shows​ ​students​ ​set-up​ ​for​ ​the​ ​preparation​ ​and​ ​collection​ ​of​ ​oxygen gas
(a)​ ​Name​ ​substance​ ​X​ ​used (b)​ ​Write​ ​an​ ​equation​ ​to​ ​show​ ​the​ ​reaction​ ​of​ ​sodium​ ​peroxide​ ​with​ ​the​ ​substance​ ​named in​ ​1(a) 5.​ ​Water​ ​and​ ​hydrogen 1. (a)​ ​Hydrogen​ ​can​ ​reduce​ ​coppers​ ​Oxide​ ​but​ ​not​ ​alluminium​ ​oxide.​ ​Explain (b)​ ​When​ ​water​ ​reacts​ ​with​ ​potassium​ ​metal​ ​the​ ​hydrogen​ ​produced​ ​ignites​ ​explosively ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​on​ ​the​ ​surface​ ​of​ ​water. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(i)​ ​What​ ​causes​ ​this​ ​ignition? ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(ii)​ ​Write​ ​an​ ​equation​ ​to​ ​show​ ​how​ ​this​ ​ignition​ ​occurs 2.
(a)​ ​Hydrogen​ ​can​ ​reduce​ ​coppers​ ​Oxide​ ​but​ ​not​ ​alluminium​ ​oxide.​ ​Explain (b)​ ​When​ ​water​ ​reacts​ ​with​ ​potassium​ ​metal​ ​the​ ​hydrogen​ ​produced​ ​ignites​ ​explosively ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​on​ ​the​ ​surface​ ​of​ ​water. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(i)​ ​What​ ​causes​ ​this​ ​ignition? ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(ii)​ ​Write​ ​an​ ​equation​ ​to​ ​show​ ​how​ ​this​ ​ignition​ ​occurs 2. In​ ​an experiment,​ ​dry​ ​hydrogen​ ​gas​ ​was​ ​passed​ ​over​ ​hot​ ​copper​ ​(II)​ ​oxide​ ​in​ ​a​ ​combustion ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​tube​ ​as​ ​ ​shown​ ​in​ ​the​ ​diagram​ ​below:-
(a)​ ​Complete​ ​the​ ​diagram​ ​to​ ​show​ ​how​ ​the​ ​other​ ​product,​ ​substance​ ​R​ ​could​ ​be​ ​collected ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​in​ ​the​ ​laboratory. (b)​ ​Describe​ ​how​ ​copper​ ​could​ ​be​ ​obtained​ ​from​ ​the​ ​mixture​ ​containing​ ​copper​ ​(II)​ ​oxide
3.​ ​ ​ ​ ​ ​The​ ​setup​ ​below​ ​was​ ​used​ ​to​ ​investigate​ ​the​ ​reaction​ ​between​ ​metals​ ​and​ ​water.
​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(ii)​ ​Write​ ​an​ ​equation​ ​to​ ​show​ ​how​ ​this​ ​ignition​ ​occurs 2. In​ ​an experiment,​ ​dry​ ​hydrogen​ ​gas​ ​was​ ​passed​ ​over​ ​hot​ ​copper​ ​(II)​ ​oxide​ ​in​ ​a​ ​combustion ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​tube​ ​as​ ​ ​shown​ ​in​ ​the​ ​diagram​ ​below:-
(a)​ ​Complete​ ​the​ ​diagram​ ​to​ ​show​ ​how​ ​the​ ​other​ ​product,​ ​substance​ ​R​ ​could​ ​be​ ​collected ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​in​ ​the​ ​laboratory. (b)​ ​Describe​ ​how​ ​copper​ ​could​ ​be​ ​obtained​ ​from​ ​the​ ​mixture​ ​containing​ ​copper​ ​(II)​ ​oxide
3.​ ​ ​ ​ ​ ​The​ ​setup​ ​below​ ​was​ ​used​ ​to​ ​investigate​ ​the​ ​reaction​ ​between​ ​metals​ ​and​ ​water. ​ ​ ​ ​ ​(a)​ ​Identify​ ​solid​ ​X​ ​and​ ​state​ ​its​ ​purpose ​ ​ ​ ​ ​ ​ ​ ​ ​Solid​ ​X ………………..……………………………………………………………………….. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​Purpose ……………………………………………………………………………………….. ​ ​ ​ ​ ​(b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​that​ ​produces​ ​the​ ​flame. 4. Gas​ ​P​ ​was​ ​passed​ ​over​ ​heated​ ​magnesium​ ​ribbon​ ​and​ ​hydrogen​ ​gas​ ​was​ ​collected​ ​as shown in the​ ​diagram​ ​below:
(i)​ ​Name​ ​gas​ ​P ...............................................................................................................
​ ​ ​ ​ ​(b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​that​ ​produces​ ​the​ ​flame. 4. Gas​ ​P​ ​was​ ​passed​ ​over​ ​heated​ ​magnesium​ ​ribbon​ ​and​ ​hydrogen​ ​gas​ ​was​ ​collected​ ​as shown in the​ ​diagram​ ​below:
(i)​ ​Name​ ​gas​ ​P ............................................................................................................... (ii)​ ​Write​ ​an​ ​equation​ ​of​ ​the​ ​reaction​ ​that​ ​takes​ ​place​ ​in​ ​the​ ​combustion​ ​tube (iii)​ ​State​ ​one​ ​precaution​ ​necessary​ ​at​ ​the​ ​end​ ​of​ ​this​ ​experiment 5.​ ​ ​ ​ ​ ​ ​ ​When​ ​hydrogen​ ​is​ ​burnt​ ​and​ ​the​ ​product​ ​cooled,​ ​the​ ​following​ ​results​ ​are​ ​obtained​ ​as shown ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​in​ ​the​ ​diagram​ ​below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(a)​ ​Write​ ​the​ ​equation​ ​for​ ​the​ ​formation​ ​of​ ​liquid​ ​Y ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(b)​ ​Give​ ​a​ ​chemical​ ​test​ ​for​ ​liquid​ ​Y
6. Jane​ ​set-up​ ​the​ ​experiment​ ​as​ ​shown​ ​below​ ​to​ ​collect​ ​a​ ​gas.​ ​The​ ​wet​ ​sand​ ​was​ ​heated before heating​ ​Zinc granules (a)​ ​Complete​ ​the​ ​diagram​ ​for​ ​the​ ​laboratory​ ​preparation​ ​of​ ​the​ ​gas (b)​ ​Why​ ​was​ ​it​ ​necessary​ ​to​ ​heat​ ​wet​ ​sand​ ​before​ ​heating​ ​Zinc​ ​granules? 7.
(ii)​ ​Write​ ​an​ ​equation​ ​of​ ​the​ ​reaction​ ​that​ ​takes​ ​place​ ​in​ ​the​ ​combustion​ ​tube (iii)​ ​State​ ​one​ ​precaution​ ​necessary​ ​at​ ​the​ ​end​ ​of​ ​this​ ​experiment 5.​ ​ ​ ​ ​ ​ ​ ​When​ ​hydrogen​ ​is​ ​burnt​ ​and​ ​the​ ​product​ ​cooled,​ ​the​ ​following​ ​results​ ​are​ ​obtained​ ​as shown ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​in​ ​the​ ​diagram​ ​below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(a)​ ​Write​ ​the​ ​equation​ ​for​ ​the​ ​formation​ ​of​ ​liquid​ ​Y ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(b)​ ​Give​ ​a​ ​chemical​ ​test​ ​for​ ​liquid​ ​Y
6. Jane​ ​set-up​ ​the​ ​experiment​ ​as​ ​shown​ ​below​ ​to​ ​collect​ ​a​ ​gas.​ ​The​ ​wet​ ​sand​ ​was​ ​heated before heating​ ​Zinc granules (a)​ ​Complete​ ​the​ ​diagram​ ​for​ ​the​ ​laboratory​ ​preparation​ ​of​ ​the​ ​gas (b)​ ​Why​ ​was​ ​it​ ​necessary​ ​to​ ​heat​ ​wet​ ​sand​ ​before​ ​heating​ ​Zinc​ ​granules? 7. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(a)​ ​Between​ ​N​ ​and​ ​M​ ​which​ ​part​ ​should​ ​be​ ​heated​ ​first?​ ​Explain (b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​occurring​ ​in​ ​the​ ​combustion​ ​tube. 8.
7. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(a)​ ​Between​ ​N​ ​and​ ​M​ ​which​ ​part​ ​should​ ​be​ ​heated​ ​first?​ ​Explain (b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​occurring​ ​in​ ​the​ ​combustion​ ​tube. 8. The​ ​set-up​ ​below​ ​was​ ​used​ ​to​ ​investigate​ ​electrolysis​ ​of​ ​a​ ​certain​ ​molten​ ​compound;- (a)​ ​Complete​ ​the​ ​circuit​ ​by​ ​drawing​ ​the​ ​cell​ ​in​ ​the​ ​gap​ ​left​ ​in​ ​the​ ​diagram (b)​ ​Write​ ​half-cell​ ​equation​ ​to​ ​show​ ​what​ ​happens​ ​at​ ​the​ ​cathode (c)​ ​Using​ ​an​ ​arrow​ ​show​ ​the​ ​direction​ ​of​ ​electron​ ​flow​ ​in​ ​the​ ​diagram​ ​above
9.Hydrogen​ ​can​ ​be​ ​prepared​ ​by​ ​reacting​ ​zinc​ ​with​ ​dilute​ ​hydrochloric​ ​acid. a)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​reaction. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​b)​ ​Name​ ​an​ ​appropriate​ ​drying​ ​agent​ ​for​ ​hydrogen​ ​gas. c)​ ​Explain​ ​why​ ​copper​ ​metal​ ​cannot​ ​be​ ​used​ ​to​ ​prepare​ ​hydrogen​ ​gas. d)​ ​Hydrogen​ ​burns​ ​in​ ​oxygen​ ​to​ ​form​ ​an​ ​oxide. ​ ​ ​ ​(i)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​reaction.
c)​ ​Explain​ ​why​ ​copper​ ​metal​ ​cannot​ ​be​ ​used​ ​to​ ​prepare​ ​hydrogen​ ​gas. d)​ ​Hydrogen​ ​burns​ ​in​ ​oxygen​ ​to​ ​form​ ​an​ ​oxide. ​ ​ ​ ​(i)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​reaction. ​ ​ ​ ​(ii)​ ​State​ ​two​ ​precautions​ ​that​ ​must​ ​be​ ​taken​ ​before​ ​the​ ​combustion​ ​begins​ ​and​ ​at​ ​the end​ ​of ​ ​ ​ ​ ​ ​ ​ ​ ​the​ ​combustion. e)​ ​Give​ ​two​ ​uses​ ​of​ ​hydrogen​ ​gas. f)​ ​When​ ​zinc​ ​is​ ​heated​ ​to​ ​redness​ ​in​ ​a​ ​current​ ​of​ ​steam,​ ​hydrogen​ ​gas​ ​is​ ​obtained.​ ​Write an ​ ​ ​ ​ ​equation​ ​for​ ​the​ ​reaction. g)​ ​Element​ ​Q​ ​reacts​ ​with​ ​dilute​ ​acids​ ​but​ ​not​ ​with​ ​cold​ ​water.​ ​Element​ ​R​ ​does​ ​not​ ​react with ​ ​ ​ ​ ​dilute​ ​acids.​ ​Elements​ ​S​ ​displaces​ ​element​ ​P​ ​from​ ​its​ ​oxide.​ ​P​ ​reacts​ ​with​ ​cold​ ​water. Arrange ​ ​ ​ ​ ​the​ ​four​ ​elements​ ​in​ ​order​ ​of​ ​their​ ​reactivity,​ ​starting​ ​with​ ​the​ ​most​ ​reactive. h)​ ​Explain​ ​how​ ​hydrogen​ ​is​ ​used​ ​in​ ​the​ ​manufacture​ ​of​ ​margarine. 10. a)​ ​The​ ​set-up​ ​below​ ​ ​is​ ​used​ ​to​ ​investigate​ ​the​ ​properties​ ​ ​of​ ​ ​hydrogen.
h)​ ​Explain​ ​how​ ​hydrogen​ ​is​ ​used​ ​in​ ​the​ ​manufacture​ ​of​ ​margarine. 10. a)​ ​The​ ​set-up​ ​below​ ​ ​is​ ​used​ ​to​ ​investigate​ ​the​ ​properties​ ​ ​of​ ​ ​hydrogen. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​i)​ ​On​ ​the​ ​diagram,​ ​indicate​ ​what​ ​should​ ​be​ ​done​ ​for​ ​the​ ​reaction​ ​to​ ​occur ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ii)​ ​Hydrogen​ ​gas​ ​is​ ​allowed​ ​to​ ​pass​ ​through​ ​the​ ​tube​ ​for​ ​some​ ​time​ ​before​ ​it​ ​is​ ​lit.​ ​Explain ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​iii)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​reaction​ ​that​ ​occurs​ ​in​ ​the​ ​combustion​ ​tube ​ ​ ​ ​ ​ ​ ​ ​ ​ ​iv)​ ​When​ ​the​ ​reaction​ ​is​ ​complete,​ ​hydrogen​ ​gas​ ​is​ ​passed​ ​through​ ​the​ ​apparatus​ ​until​ ​they ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​cool​ ​down​ ​.​ ​ ​ ​Explain ​ ​ ​ ​ ​ ​ ​ ​ ​ ​v)​ ​What​ ​property​ ​of​ ​hydrogen​ ​is​ ​being​ ​investigated? ​ ​ ​ ​ ​ ​ ​ ​ ​vi)​ ​What​ ​observation​ ​confirms​ ​the​ ​property​ ​stated​ ​in​ ​(​v)​ ​above? ​ ​ ​ ​ ​ ​ ​ ​ ​vii)​ ​Why​ ​is​ ​zinc​ ​oxide​ ​not​ ​used​ ​to​ ​investigate​ ​this​ ​property​ ​of​ ​hydrogen​ ​gas? 11.
​ ​ ​ ​ ​ ​ ​ ​ ​vi)​ ​What​ ​observation​ ​confirms​ ​the​ ​property​ ​stated​ ​in​ ​(​v)​ ​above?

​ ​ ​ ​ ​ ​ ​ ​ ​vii)​ ​Why​ ​is​ ​zinc​ ​oxide​ ​not​ ​used​ ​to​ ​investigate​ ​this​ ​property​ ​of​ ​hydrogen​ ​gas?

11.

The​ ​set​ ​up​ ​below​ ​was​ ​used​ ​to​ ​collect​ ​gas​ ​K,​ ​produced​ ​by​ ​the​ ​reaction​ ​between​ ​water​ ​and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​calcium​ ​metal.

(a)​ ​Name​ ​gas​ ​K……………………………………………………………..

(b)​ ​At​ ​the​ ​end​ ​of​ ​the​ ​experiment,​ ​the​ ​solution​ ​in​ ​the​ ​beaker​ ​was​ ​found​ ​to​ ​be​ ​a​ ​weak​ ​base.

Explain ​ ​ ​ ​ ​ ​ ​why​ ​the​ ​solution​ ​is​ ​a​ ​weak​ ​base
ATOMIC STRUCTURE AND THE PERIODIC TABLE Preface The structure of the atom is extensively covered here. The periodic table is the arrangement of atoms of elements based on their atomic structure. Emphasis on the trends across and down the periodic table of atoms is important for the teacher facilitator. This work should be covered before “Chemical bonding and structure”. The two complements each other in understanding periodicity. Candidate-user preparing for any secondary level chemistry from members of A.ATOMIC STRUCTURE The atom is the smallest particle of an element that take part in a chemical reaction.The atom is made up of three subatomic particle: (i)Protons (ii)Electrons (iii)Neutrons (i)Protons 1.The proton is positively charged 2.Is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons in a atom of an element is its Atomic number (ii)Electrons 1.The Electrons is negatively charged 2.Is found in fixed regions surrounding the centre of an atom called energy levels/orbitals. 3.It has a relative mass 1/1840 4.The number of protons and electrons in a atom of an element is always equal (iii)Neutrons 1.The Neutron is neither positively or negatively charged thus neutral. 2.Like protons it is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons and neutrons in a atom of an element is its Mass number Diagram showing the relative positions of protons ,electrons and neutrons in an atom of an element
2 Diagram showing the relative positions of protons, electrons and neutrons in an atom of Carbon The table below show atomic structure of the 1st twenty elements.
Candidate-user preparing for any secondary level chemistry from members of A.ATOMIC STRUCTURE The atom is the smallest particle of an element that take part in a chemical reaction.The atom is made up of three subatomic particle: (i)Protons (ii)Electrons (iii)Neutrons (i)Protons 1.The proton is positively charged 2.Is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons in a atom of an element is its Atomic number (ii)Electrons 1.The Electrons is negatively charged 2.Is found in fixed regions surrounding the centre of an atom called energy levels/orbitals. 3.It has a relative mass 1/1840 4.The number of protons and electrons in a atom of an element is always equal (iii)Neutrons 1.The Neutron is neither positively or negatively charged thus neutral. 2.Like protons it is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons and neutrons in a atom of an element is its Mass number Diagram showing the relative positions of protons ,electrons and neutrons in an atom of an element
2 Diagram showing the relative positions of protons, electrons and neutrons in an atom of Carbon The table below show atomic structure of the 1st twenty elements. Element Symbol Protons Electrons Neutrons Atomic number Mass number Hydrogen H 1 1 0 1 1 Helium He 2 2 2 2 4 Lithium Li 3 3 4 3 7 Beryllium Be 4 4 5 4 9 Boron B 5 5 6 5 11 Carbon C 6 6 6 6 12 Nitrogen N 7 7 7 7 14 Oxygen O 8 8 8 8 16 Fluorine F 9 9 10 9 19 Neon Ne 10 10 10 10 20
3 Sodium Na 11 11 12 11 23 Magnesium Mg 12 12 12 12 24 Aluminium Al 13 13 14 13 27 Silicon Si 14 14 14 14 28 Phosphorus P 15 15 16 15 31 Sulphur S 16 16 16 16 32 Chlorine Cl 17 17 18 17 35 Argon Ar 18 18 22 18 40 Potassium K 19 19 20 19 39 Calcium Ca 20 20 20 20 40 Most atoms of elements exist as isotopes.
3.It has a relative mass 1/1840 4.The number of protons and electrons in a atom of an element is always equal (iii)Neutrons 1.The Neutron is neither positively or negatively charged thus neutral. 2.Like protons it is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons and neutrons in a atom of an element is its Mass number Diagram showing the relative positions of protons ,electrons and neutrons in an atom of an element
2 Diagram showing the relative positions of protons, electrons and neutrons in an atom of Carbon The table below show atomic structure of the 1st twenty elements. Element Symbol Protons Electrons Neutrons Atomic number Mass number Hydrogen H 1 1 0 1 1 Helium He 2 2 2 2 4 Lithium Li 3 3 4 3 7 Beryllium Be 4 4 5 4 9 Boron B 5 5 6 5 11 Carbon C 6 6 6 6 12 Nitrogen N 7 7 7 7 14 Oxygen O 8 8 8 8 16 Fluorine F 9 9 10 9 19 Neon Ne 10 10 10 10 20
3 Sodium Na 11 11 12 11 23 Magnesium Mg 12 12 12 12 24 Aluminium Al 13 13 14 13 27 Silicon Si 14 14 14 14 28 Phosphorus P 15 15 16 15 31 Sulphur S 16 16 16 16 32 Chlorine Cl 17 17 18 17 35 Argon Ar 18 18 22 18 40 Potassium K 19 19 20 19 39 Calcium Ca 20 20 20 20 40 Most atoms of elements exist as isotopes. Isotopes are atoms of the same element, having the same number of protons/atomic number but different number of neutrons/mass number. By convention, isotopes are written with the mass number as superscript and the atomic number as subscript to the left of the chemical symbol of the element. i.e.
Isotopes are atoms of the same element, having the same number of protons/atomic number but different number of neutrons/mass number. By convention, isotopes are written with the mass number as superscript and the atomic number as subscript to the left of the chemical symbol of the element. i.e. mass number atomic number m n X symbol of element Below is the conventional method of writing the 1st twenty elements showing the mass numbers and atomic numbers; 2He 4Be 6C 147N 168O 10Ne 12Mg 14Si 16S 18Ar 20C The table below shows some common natural isotopes of some elements Element Isotopes Protons Electrons Neutrons Atomic number Mass number Hydrogen 1H(deuterium) 31H(Tritium) 1 1 1 1 1 1 0 2 3 1 1 1 1 2 17Cl 3717Cl 17 17 17 17 18 20 17 17 35 19K 4019K 19 19 19 19 20 21 19 19 39 40
4 4119K 19 19 22 19 8O 188O 8 8 8 8 8 10 8 8 16 92U 23892U 92 92 92 92 143 146 92 92 235 10Ne 10Ne 10 10 10 10 10 10 12 10 11 10 10 10 22 20 21 The mass of an average atom is very small (10-22 g).Masses of atoms are therefore expressed in relation to a chosen element. The atom recommended is 12C isotope whose mass is arbitrarily assigned as 12.000 atomic mass units(a.m.u) .
i.e. mass number atomic number m n X symbol of element Below is the conventional method of writing the 1st twenty elements showing the mass numbers and atomic numbers; 2He 4Be 6C 147N 168O 10Ne 12Mg 14Si 16S 18Ar 20C The table below shows some common natural isotopes of some elements Element Isotopes Protons Electrons Neutrons Atomic number Mass number Hydrogen 1H(deuterium) 31H(Tritium) 1 1 1 1 1 1 0 2 3 1 1 1 1 2 17Cl 3717Cl 17 17 17 17 18 20 17 17 35 19K 4019K 19 19 19 19 20 21 19 19 39 40
4 4119K 19 19 22 19 8O 188O 8 8 8 8 8 10 8 8 16 92U 23892U 92 92 92 92 143 146 92 92 235 10Ne 10Ne 10 10 10 10 10 10 12 10 11 10 10 10 22 20 21 The mass of an average atom is very small (10-22 g).Masses of atoms are therefore expressed in relation to a chosen element. The atom recommended is 12C isotope whose mass is arbitrarily assigned as 12.000 atomic mass units(a.m.u) . All other atoms are compared to the mass of 12C isotope to give the relative at The relative atomic mass(RAM) is therefore defined as “the mass of average atom of an element compared to 1/12 an atom of 12C isotope whose mass is arbitrarily fixed as 12.000 atomic mass units(a.m.u) ” i.e; RAM = mass of atom of an element 1/12 of one atom of 12C isotope Accurate relative atomic masses (RAM) are got from the mass spectrometer. Mass spectrometer determines the isotopes of the element and their relative abundance/availability. Using the relative abundances/availability of the isotopes, the relative atomic mass (RAM) can be determined /calculated as in the below examples.
All other atoms are compared to the mass of 12C isotope to give the relative at The relative atomic mass(RAM) is therefore defined as “the mass of average atom of an element compared to 1/12 an atom of 12C isotope whose mass is arbitrarily fixed as 12.000 atomic mass units(a.m.u) ” i.e; RAM = mass of atom of an element 1/12 of one atom of 12C isotope Accurate relative atomic masses (RAM) are got from the mass spectrometer. Mass spectrometer determines the isotopes of the element and their relative abundance/availability. Using the relative abundances/availability of the isotopes, the relative atomic mass (RAM) can be determined /calculated as in the below examples. a) Chlorine occurs as 75% 3517Cl and 25% 3717Cl isotopes. Calculate the relative atomic mass of Chlorine. Working 100 atoms of chlorine contains 75 atoms of 3517Cl isotopes 100 atoms of chlorine contains 75 atoms of 3717Cl isotopes Therefore; RAM of chlorine = ( 75/100 x 35) + 25/100 x 37 = 35.5 Note that: Relative atomic mass has no units More atoms of chlorine exist as 3517Cl(75%) than as 3717Cl(25%) therefore RAM is nearer to the more abundant isotope. 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.
Calculate the relative atomic mass of Chlorine. Working 100 atoms of chlorine contains 75 atoms of 3517Cl isotopes 100 atoms of chlorine contains 75 atoms of 3717Cl isotopes Therefore; RAM of chlorine = ( 75/100 x 35) + 25/100 x 37 = 35.5 Note that: Relative atomic mass has no units More atoms of chlorine exist as 3517Cl(75%) than as 3717Cl(25%) therefore RAM is nearer to the more abundant isotope. 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.
Working 100 atoms of chlorine contains 75 atoms of 3517Cl isotopes 100 atoms of chlorine contains 75 atoms of 3717Cl isotopes Therefore; RAM of chlorine = ( 75/100 x 35) + 25/100 x 37 = 35.5 Note that: Relative atomic mass has no units More atoms of chlorine exist as 3517Cl(75%) than as 3717Cl(25%) therefore RAM is nearer to the more abundant isotope. 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.