List of chemistry mnemonics

A mnemonic is a memory aid used to improve long term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics. This article contains the list of certain mnemonics in chemistry.

Orbitals

Sequence of orbitals
Further information: Spectroscopic notation
s p d f g h i k
  • Sober Physicists Don't Find Giraffes Hiding In Kitchens.

Note: After the k shell, they follow alphabetical order (skipping s and p as they came earlier).[1]

Aufbau principle
1s2 2s2 2p6 3s2 3p6 4s2 3d10 ...

The order of sequence of atomic orbitals (according to Madelung rule or Klechkowski rule) can be remembered by the following.[2]

Order in which orbitals are arranged by increasing energy according to the Madelung rule. Each diagonal red arrow corresponds to a different value of n + l.

Periodic table
Main article: Periodic table

Periods
Main article: Period (periodic table)

Periods 1, 2 and 3
H He Li Be B C N O F Ne Na (sodium) Mg Al Si P S Cl Ar
  • Native Magpies Always Sit Peacefully Searching Clear Areas.[3]
  • Naval Magistrates Always Signal Per Siren, Claiming Adequacy.[4]
  • Naughty Margaret Always Sighs, "Please Stop Clowning Around."[5]
  • Nellie's Naughty Magpie Always Sings Pop Songs Clearly After Killing Cathy.[5]
  • All Silicon Ports. Superman Clean Argon's K-Capture.[6]
  • Happy Harry Listens B B C Network Over France Nevertheless Nothing More Arose So Peter Stopped Cleaning Airgun K Ca.[7]
  • Ha. Healthy Little Beggar Boys Catching Newts Or Fish.[8]
  • Hell, Here Little Beatniks Brandish Countless Number Of Flick kNives.[9] Nagging Maggie Always Sighs, "Please Stop Clowning Around." [5] (adapted)
  • Hi Helium. Little Berries Borrow Carbs, NO Fight Needed.

Period 4
K (Potassium) Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
  • Kindly Cannibals Scare Timid Visitors, 'n' Cruelly Menace Female Communist Nitwits Cuddling Zany Gabbling Geese Astride Several Brutal Kangaroos.[4]
  • In reverse order: Kry Brother! SeAs of Germany and Gaul sink copper ships Nice and Cold From Manx to Crimea, Vancouver to Timor, and Scandinavia to the California Koast.[10]
  • Kind Cats Scare Tiny Vicious Creatures, Maintaining Feline Connections Nice, Cute & Zen. Gallium Germinates As Selene Brings Krypton.

Period 5
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
  • Rabbit Servers Yell, "Zircon Nebulas Most Technically Rule Rhodes & Paddle Against Cadence !". In San Sebastian, Tellura Isolated Xenon.

Transition metals

First
Sc Ti V Cr Mn Fe Co Ni Cu Zn
  • Scary Tiny Vicious Creatures are Mean; Females Come to NightClub Zen.[11]
  • SucTion VelCro Man Fears CoNiC uZi.

Second
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd
  • Yes S(Z)ir, Nob. Most Technicians Rub Rod's Pale Silver Cadillac.[11]

Third
La ... Hf Ta W Re Os Ir Pt Au Hg
  • Larry's Half Taken, Wendy Reached Out H(I)er Plate Audibly, Helga.[11]
  • Late Harry Took Walk, Reached Office In Pajamas, After an Hour.

Lanthanides and actinides
Main articles: Lanthanides and actinides

Lanthanides
(La) Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
  • Ladies Can't Put Needles Properly in Slot-machines. Every Girl Tries Daily, However, Every Time You'd_be Lose.[12]
  • Languid Centaurs Praise Ned's Promise of Small European Garden Tubs; Dinosaurs Hobble Erratically Thrumming Yellow Lutes.[13]

Actinides
(Ac) Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
  • Radiant Acting Thoroughly Protects yoUr Nepotism, Plutocratic America Cures-me & Berkeley California, Einstein Firmly Mended Noble Lawreins.[14]
  • According to Thor Protects: Uranus, Neptune, and Pluto. Amy Cured Berkeley, California. Einstein and Fermi Made Noble Laws.[11]

56 elements in sequence
He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba
Indian Sons Sobbing Tears In Xcess Cease Bawling.[6]

Groups
Main article: Group (periodic table)

Group 1 (alkali metals)
Li Na K Rb Cs Fr

Lithium, Sodium, Potassium, Rubidium, Caesium, Francium

  • Little Nasty Kids Rub Cats Fur
  • Little Naughty Kids Ruin Ben's Convenient Store Forever
  • Little Nathan Knew Rubies Cost Fortunes
  • Little Naughty Kids Rob Cold Fries


Group 2 (alkaline earth metals)
Be Mg Ca Sr Ba Ra

Beryllium, Magnesium, Calcium, Strontium, Barium, Radium

  • Bearded Muggers Came Straight Back Rapidly.
  • Beer Mugs Can Serve Bar Rats.[11]
  • Ben Meg & Casia Stroll away to Bar of Radium

Group 13
B Al Ga In Tl

Boron, Aluminium, Gallium, Indium, Thallium

  • Bowler Ali Gave Instant Tea
  • BAG IT
  • Bears Always Gave Indians Trouble

Group 14
C Si Ge Sn Pb

Carbon, Silicon, Germanium, Tin, Lead

  • Can Simple Germans Snare (Tiny) Public (Lead)?[11]

Group 16 (Chalcogens)
O S Se Te Po Lv

Oxygen, Sulfur, Selenium, Tellurium, Polonium

  • Old TSangpo Seems Terribly Polluted Lately.[11]
  • Ottoman Syria Sends Textiles to Poland-Lithuania.

Group 17 (Halogens)
F Cl Br I At Ts

Fluorine, Chlorine, Bromine, Iodine, Astatine, Tennessine

  • Funny Clowns Broil Innocent Ants.[11]
  • Fast Clouds Break In Atlantis.[14]
  • Father Clark B(r)lesses Ivan A(s)tlast.

Group 18 (noble gases)
He Ne Ar Kr Xe Rn

Helium, Neon, Argon, Krypton, Xenon, Radon, Oganesson

  • Hero Needs Arguable Kryptic Xes. Right-on.[14]
  • He Never Arrived; Karen eXited with Ron.[11]
  • He Needs A Kickin', Xylophone-playin' Racehorse! (And... Oh, gee, now we need to add Oganesson (Og)!)

Properties of elements

Abundance of elements on earth's crust
[Oxygen(O)] > [Silicon(Si)] > [Aluminium(Al)] > [Iron(Fe)] > [Calcium(Ca)] > [Sodium (Na)] > [Potassium(K)] > [Magnesium (Mg)]
(The rest makes only 1%)
  • Only Strong Athletes In College Study Past Midnight
  • Oh, see(Si), Alfie(Fe) Cannot(Na) Kiss Meg(Mg)

As they are present in trace quantities they are measured in parts per million(ppm).

Activity series of metals
Main article: Reactivity series
Potassium>Sodium>Calcium>Magnesium>Aluminium>(Carbon)*>Zinc>Iron>Tin>Lead>(Hydrogen)*>Copper>Mercury>Silver>Gold>Platinum
  • Please Stop Calling Me A Cute Zebra I Like Her Call Smart Goat
  • Please Stop Calling Me A Carless Zebra Instead Try Learning How Copper Miners Save Gold Pit
  Popular Scientists Can Create A Zoo In Low Humid Temperatures, Mercury Silver Gold

Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead, Hydrogen, Copper, Mercury, Silver Gold


Another way to memorize the Reactivity series in order is by Using the Story-Link Memory Technique.[15]

Note that Carbon and Hydrogen are non-metals, used as a baseline.

K > Na > Mg > Al > Zn > Cr > Fe > Pb > H > Cu > Au
  • Kangaroos Naturally Muck About in Zoos For Purple Hippos Chasing Aardvarks.[16]
  • Katty's Naughty Cat Mingled with Alice and Zarina; Fearlessly Plundering Her Cupboard of Gold.[17]
  • Papa Said Call Me After Zinc Interacts Tin Leading Hydrogen Co-operate Mr. Sylvester to Gain Popularity.[18]
K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > Cu > Ag > Au >Pt
  • Pretty(Potassium) Sally(Sodium) Could(Calcium) Marry(Magnesium) A(Aluminium) Crazy(Carbon) Zulu(Zinc) IN(Iron/Nickel) Tree(Tin) Lined(Lead) House(Hydrogen) Causing(Copper) Strangely(Silver) Glancing(Gold) People(Platinum).
Li > K > Ba > Sr > Ca > Na > Mg > Al > Mn > Zn > Cr > Fe > Cd > Co > Ni > Sn > Pb
  • Li K Ba Sr Ca Na. Mg Al Mn Zn. Cr Fe Cd, Co Ni Sn Pb. That is.

Electronegativity
Main article: Electronegativity
Fluorine > Oxygen > Chlorine > Nitrogen > Bromine > Iodine > Sulfur > Carbon > Hydrogen ≥ Phosphorus
  • Pronounce: FOClN BrIS CHP.[19]

(F)irst (O)ff, (Cl)oud (N)ow; (Br)ing (I)n (S)ome (C)aps, (H)ats, and (P)ants. (First off, cloud now. Bring in some caps, hats {and} pants.)

Electrochemical series
Main article: Standard electrode potential (data page)
Potassium > Sodium > Calcium > Magnesium > Aluminium > Zinc > Iron > Tin > Lead > Hydrogen > Copper > Silver > Gold
  • Popular Scientists Can Make A Zoo In The Low Humid Country More(Mercury) Satisfactorily (Gold).
  • Paddy Still Could Marry A Zulu In The Lovely Honolulu Causing Strange Gazes.
  • Please Stop Calling Me A Crazy Zombie If That Large Hippo Can’t Swim, Glug, glug.
  • Passive Sarcasm Can Mutate Angry Zombies InTo Large Hypocritical Cold Sexy Guys.
  • Please Send Charlie's Monkeys And Zebras In Cages Securely Guarded
  • Police Sergeant Charles M A C ZINTL Has Caught Me Stealing Gold Plates

Reactions and ions

Redox reactions

A redox reaction is a chemical reaction in which there is a change in oxidation state of atoms participating in the reaction.

Ions

An atom (or ion) whose oxidation number increases in a redox reaction is said to be oxidized (and is called a reducing agent). It is accomplished by loss of one or more electrons. The atom whose oxidation number decreases gains (receives) one or more electrons and is said to be reduced. This relation can be remembered by the following mnemonics.

  • Leo says Ger! or Leo the lion, Ger! can be used to represent Loss of electron is oxidation; Gain of electron is reduction.[20][21]
  • Oil Rig: Oxidation is loss; Reduction is gain (of electrons).[22]

Cations and anions

Cations are positively (+) charged ions while anions are negatively (−) charged. This can be remembered with the help of the following mnemonics.

  • Cats have paws ⇔ Cations are pawsitive.[23]
  • Ca+ion: The letter t in cation looks like a + (plus) sign.[24]
  • An anion is a negative ion. (Anegativeion ⇒ Anion).[25]

Cation vs. anion: positive vs. negative

The t in cation looks like a plus sign: "ca+ion".

Cation is positive, anion is negative.[26]

  • Cat ions are pawsitive

Oxidation vs. reduction: electrochemical cell and electron gain/loss

AN OIL RIG CAT:

At the ANode, Oxidation Involves Loss of electrons.

Reduction Involves Gaining electrons at the CAThode.[26]

LOAN - Left Anode Oxidation Negative. In written representation of galvanic cell, anode is written on the left. It is the electrode where oxidation takes place. It is the negative electrode. Obviously, the opposite properties (Right/Cathode/Reduction/Positive) are found on the cathode. Hence, by remembering LOAN mnemonic, we can arrive at the corresponding properties for the cathode.

LEO says GER:

"Loss of Electrons, Oxidation; Gain of Electrons, Reduction".[27]

Electrodes

An electrode in which oxidation takes place is called an anode while in that which reduction takes place is called cathode. This applies for both electrolytic and electrochemical cells, though the charge on them reverses. The red cat and an ox mnemonics are useful to remember the same.

  • Red cat: Reduction at cathode
An ox: Anode for oxidation.[28]
  • The words oxidation and anode, both begin with vowels.
Also, both reduction and cathode begin with consonants.[25]
  • Fat Cat: electrons flow From Anode To Cathode
  • LOAN: Left side;Oxidation;Anode;Negative.

Compounds

Diatomic molecules

Molecules exhibiting diatomic structures can be remembered through the following mnemonics.

Hydrogen, Oxygen, Nitrogen, Fluorine, Chlorine, Bromine, Iodine
  • Have No Fear Of Ice Cold Beer. [29]
  • Horses Need Oats For Clear Brown Eyes (I's).
  • Her Nana's Only Functioning Clicker Broke Instantly.[30]
  • BrINClHOF: say Brinkelhof.[31]
  • I Bring Clay For Our New House.[11]

Hydrogen bonds

Hydrogen forms hydrogen bonds with three elements which are nitrogen (N), oxygen (O) and fluorine (F). The names of these elements can be remembered by the following mnemonic.

  • Hydrogen is FON! (fun).[25]

Polyatomic ions: −ate and -ite ions
Sulfate, Phosphate, Carbonate, Chlorate, Bromate, Iodate, Nitrate
  • Super Popeye Constantly Clubbed Brutus In Nevada.
Nitrate, Bromate, Carbonate, Iodate, Chlorate, Chromate, Sulfate, Phosphate
  • Nick Brit the Camel ate an Inky Clam with Crêpes for Supper in Phoenix.

Number of consonants denotes number of oxygen atoms. Number of vowels denotes negative charge quantity. Inclusion of the word "ate" signifies that each ends with the letters a-t-e. To use this for the -ite ions, simply subtract one oxygen but keep the charge the same.

Organic chemistry

Prefixes for naming carbon chains

The prefixes for naming carbon chains containing one to four carbons. For chains containing five or more carbons, the inorganic prefixes (pent, hex, etc.) are used.

Meth Eth Prop But
1 2 3 4
  • Monkeys Eat Peeled Bananas

Carboxylic acids

Common names of homogeneous aliphatic carboxylic acids,

Formic, Acetic, Propionic, Butyric, Valeric, Caproic
  • Frogs Are Polite, Being Very Courteous.[32]

Dicarboxylic acids

The sequence of dicarboxylic acids can be remembered with following mnemonics.

Oxalic, Malonic, Succinic, Glutaric, Adipic, Pimelic, Suberic, Azelaic, Sebacic
  • Oh My, Such Good Apples.[33]
  • Oh My Stars, Green Apples.
  • Oh My, Such Good Apple Pie, Sweet As Sugar.[34][35]
  • Oh My Stars, Go Ahead Please[25]
  • OMSGAP - is a phonetic word for the first letters of the first six dicarboxylic acids above in sequence.

Aromatic compounds

m-directing groups
Quaternary aminoEsterSulfonic acidNitroCarbonylCarboxylCyano
(-NR3+)(-COOR)(-SO3H)(-NO2)(-CHO)(-COOH)(-CN)
  • Queen Elizabeth Second's Navy Commands, Controls, Communicates.[36]

o,p-directing groups
AlkylHalogenAlkoxylAminoHydroxylAmidePhenyl
(R)(X)(OR)(-NH2-NHR-NR2)(OH)(NHCOR(C6H5)

Note: -NH2,-NHR and NR2 are para directing groups but not -NR3+

E-Z notation for isomers

"E" for enemies. i.e higher priority groups on opposite sides. Z form has higher priority groups on same side.[26]

"Z zame zide" i.e. high priority groups on same side.

Cis–trans isomerism
Main article: Cis–trans isomerism

Cis starts with a C and the functional groups form a C.

Trans, therefore is the other one by default.[26]

Benzene ring: order of substitutes

From R group moving around the ring:[26]

R group, Ortho, Meta, Para
  • Benzene likes to ROMP.

Biochemistry

Essential amino acids
Isoleucine, Leucine, Lysine, Arginine, Methionine, Phenylalanine, Threonine, Tryptophan, Histidine, Valine
  • PVT TIM HaLL[37] and TT HALL Very IMPortant.[38]
  • These Ten Valuable Acids Have Long Preserved Life In Men
  • MATT HILL, VP Matt Hill is the Vice President
  • LIFT HIM KIW(V)I
  • TV FILM HW(R)K.
  • Any Help In Learning These Little Molecules Proves Truly Valuable.[39] This method begins with the two amino acids that need some qualifications as to their requirements.
  • There as [a] fat man [that] hated vanilla icing, [but] loved Kit-Kats.

Krebs cycle

To remember Krebs cycle (citric acid cycle, tricarboxylic acid cycle);

Citrate → Aconitate → Isocitrate → Oxalosuccinate → α-Ketoglutarate → Succinate → Fumarate → Malate → Oxaloacetate
  • Caesar’s Armies Invaded Other Kingdoms Searching For Many Oranges.[19]
  • Citric Acid Is One Key Substrate For Mitochondrial Oxidation

Plant nutrients

To remember the elements necessary for agriculture;

Carbon, Hydrogen, Calcium, Iron (Fe), Magnesium (Mg), Manganese (Mn), Copper (Cu), Molybdenum, Chlorine (Cl), Boron
  • C (see) Hopkins CaFe, Mighty-good Man, Cu (see your) Money, hope they are Closed or out of Business.[40]

For remembering macronutrients;

Carbon, Hydrogen, Oxygen, Phosphorus, Potassium, Nitrogen, Sulfur, Calcium, and Magnesium
  • C. HOPKiN'S Ca Mg (C. Hopkins coffee mug).

C H O N P K Ca Mg S {CHO "N"ever "P"unch "K"ittens they'll "Ca"ll aunt "Mag" and then you are "S"crewed.

gollark: Rust.
gollark: That's worse.
gollark: WHYJIT?
gollark: ?coliru```WHY#include <stdio.h>printf("I is bad because I from c");;;;;```
gollark: You type it lots so it's short.

See also

References

First book on memory aids for chemistry by Rishabh Jain and Sambhav Jain https://www.amazon.in/Memory-Aids-Chemistry-Salt-Analysis/dp/8191003503

  1. "Mnemonic devices for: Chemistry". Mnemonic-device.eu. Retrieved 2012-08-09.
  2. Zumdahl, Steven S. and Zumdahl, Susan A. (2000), Chemistry, Houghton Mifflin, 5th ed., p. 324 ISBN 0-395-98583-8
  3. Hara, Jaclyn R.; Stanger, Gordon R.; Leony, Denisse A.; Renteria, Sandra S.; Carrillo, Alejandro; Michael, Katja (2007). "Multilingual Mnemonics for the Periodic Table". Journal of Chemical Education. 84 (12): 1918. Bibcode:2007JChEd..84.1918H. doi:10.1021/ed084p1918. ISSN 0021-9584.
  4. "Periodic Table of Elements". Retrieved 2018-02-11.
  5. "Mnemonic: Sentences to remember the elements". Ict4us.com. Retrieved 2012-07-24.
  6. "Science Jokes:11. MNEMONICS : 11.5 CHEMISTRY". Jcdverha.home.xs4all.nl. Retrieved 2012-07-24.
  7. Chemical formula. "Periodic table mnemonic (memory device)". Chemicalformula.org. Retrieved 2012-07-24.
  8. "Kids Tips for Easy Learning - Mnumonics". Betterendings.org. Retrieved 2012-07-24.
  9. Martin Berry (30 Nov 1972). A dictionary of mnemonics. New Scientist. Reed Business Information. (Eyre Mithuen). p. 535.
  10. "CHEMISTRY AND BIOCHEMISTRY A very nice site of Anatomy Mnemonics by John Berger". Img.com.tripod.com. Retrieved 2012-07-24.
  11. http://bradley.bradley.edu/~campbell/mnemonic.html
  12. Carl C. Gaither; Alma E. Cavazos-Gaither (2002). Chemically Speaking: A Dictionary of Quotations/selected and Arranged by Carl C. Gaither and Alma E. Cavazos-Gaither. CRC Press. pp. 82–83. ISBN 978-0-7503-0682-9. Retrieved 28 December 2012.
  13. "Holmium (new)". Periodic Videos.
  14. Sancy (2019). "Memorize Reactivity Series".
  15. "Sprowston Community High School - Specialist School for Performance Arts & Media". Retrieved 26 February 2016.
  16. Oon Hock Leong/ Edmund Ang Joon Aik (2007). Chemistry expression: an inquiry approach. 'O' level science (chemistry) [textbook]. Panpac Education Pte Ltd. p. 243. ISBN 9789812711656. Retrieved 27 January 2012.
  17. Syamal, Arun. "Metals, Non-metals and Metallurgy". Living Science Chemistry 10. Ratna Sagar. p. 97. ISBN 9788183322898. Retrieved 27 January 2012.
  18. "Mnemonics for chem 3 2010.ppt" (PDF). Archived from the original (PDF) on 2012-09-15. Retrieved 2012-10-16.
  19. Nick Lane (26 March 2004). Oxygen: The Molecule that Made the World. Oxford University Press. pp. 18–. ISBN 978-0-19-860783-0. Retrieved 10 August 2012.
  20. Rene Fester Kratz (2 June 2009). Molecular and Cell Biology For Dummies. John Wiley & Sons. pp. 70–. ISBN 978-0-470-43066-8. Retrieved 10 August 2012.
  21. "Chemistry - Mnemonic". Chemistrydaily.com. Retrieved 2012-07-24.
  22. Peter J. Mikulecky; Michelle Rose Gilman; Kate Brutlag (2008). "Cats+have+paws"+chem#v=onepage AP Chemistry For Dummies (Illustrated ed.). John Wiley & Sons, 2008. p. 30. ISBN 9780470389768.
  23. Kevin M. Dunn (16 March 2010). Scientific Soapmaking: The Chemistry of the Cold Process. Clavicula Press. pp. 386–. ISBN 978-1-935652-09-0. Retrieved 10 August 2012.
  24. Subhash Jain (1 January 2009). Improve Your Memory. Prabhat Prakashan. p. 117. ISBN 978-81-8430-035-2. Retrieved 28 December 2012.
  25. "MedicalMnemonics Full Abridged" (PDF). Medicalmnemonics.com. p. 36. Retrieved 16 February 2015.
  26. Zumdahl, Steven S. and Zumdahl, Susan A. (2000), Chemistry, Houghton Mifflin, 5th ed., p. 169 ISBN 0-395-98583-8
  27. Mrs Jacqueline Hilary Briggs; Rex M Heyworth. Lcg Ol Chemistry. Pearson Education South Asia. pp. 142–. ISBN 978-981-06-0008-2. Retrieved 10 August 2012.
  28. "Chemistry Mnemonics". Bookbuilder.cast.org. Retrieved 2012-07-24.
  29. Zack Ouellette
  30. http://www.freechemteacher.org/Recommended_Resources_files/Mnemonics for Chemistry.pdf
  31. Jonathan Dee; H. Stephen Stoker (2009). Organic and Biological Chemistry (5 ed.). Cengage Learning. p. 157. ISBN 9780547168043.
  32. William Henry Brown; Brent L. Iverson (2009). Organic chemistry (5, illustrated ed.). Cengage Learning. p. 621. ISBN 9780495388579. Retrieved 27 January 2012.
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  34. "Organic Chemistry Nomenclature". Translationjournal.net. 1997-11-24. Retrieved 2012-07-24.
  35. "MCAT Mnemonics Organic Chemistry Flash Cards". Cram.com. 2008-08-16. Retrieved 2012-07-24.
  36. MedicalMnemonics.com: 442 128
  37. MATT VIL PLy Essential amino acids Archived 2010-08-26 at the Wayback Machine Essential amino acids, Mnemonic.
  38. Williams, R.A.D.; Eliot, J.C. (1989). Basic and Applied Dental Biochemistry. Elsevier Health Sciences. p. 149. ISBN 0-443-03144-4.
  39. "Mnemonic: Elements necessary for agriculture". Ict4us.com. Retrieved 2012-08-09.

Further reading
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