4 Scientific vocabulary, quantities, units, symbols and nomenclature

Question 1

Explain how you work out the formula of ionic compounds ?

Answer 1

You need to know the charges on ions.

Many of these can be worked out from the position in the Periodic Table
OR
From the number in roman numerals after a name
e.g.
iron (III) sulfate - contains Fe3+ ions
iron (II) sulfate - contains Fe2+ ions

Question 2

What are the +1 ions ?

Answer 2

H+ hydrogen ions (superscript +(1))

NH4+ ammonium ions (subscript 4, superscript +(1))

Group 1 ions (e.g. Na+ sodium ions (superscript +(1)))

Question 3

What are the +2 ions ?

Answer 3

Group 2 ions (e.g. Ca2+ calcium ions (superscript +2))

Question 4

What are the +3 ions ?

Answer 4

Group 3 ions (e.g. Al3+ aluminium ions (superscript +3))

Question 5

What are the -1 ions ?

Answer 5

NO3– nitrate ions (subscript 3, superscript -(1))
OH– hydroxide ions (superscript -(1))
Group 7 ions (e.g. Br– bromide ions (superscript -(1)))

Question 6

What are the -2 ions ?

Answer 6

CO3 2– carbonate ions (subscript 3, superscript -2)
SO4 2– sulfate ions (subscript 4, superscript -2)

Question 7

What are the -3 ions ?

Answer 7

PO4 3– phosphate ions (subscript 4, superscript -3)

Question 8

How do you work out the formula of ionic compounds ?

Answer 8

The formula is worked out by balancing the number of + and – charges.

E.g.
sodium oxide contains Na+ and O2– ions
need ions in ratio: 2Na+ : 1O2–
formula = Na2O

aluminium bromide contains Al3+ and Br– ions
need ions in ratio: 1Al3+ : 3Br–
formula = AlBr3

calcium hydroxide contains Ca2+ and OH– ions
need ions in ratio: 1Ca2+ : 2OH–
formula = Ca(OH)2

magnesium nitrate contains Mg2+ and NO3– ions
need ions in ratio: 1Mg2+ : 2NO3–
formula = Mg(NO3)2

iron(III) sulfate contains Fe3+ and SO42– ions
need ions in ratio: 2Fe3+ : 3SO42–
formula = Fe2(SO4)3

Question 9

aluminium

Answer 9

Al

Question 10

argon

Answer 10

Ar

Question 11

bromine

Answer 11

Br2

Question 12

calcium

Answer 12

Ca

Question 13

carbon

Answer 13

C

Question 14

chlorine

Answer 14

Cl2

Question 15

chromium

Answer 15

Cr

Question 16

cobalt

Answer 16

Co

Question 17

copper

Answer 17

Cu

Question 18

fluorine

Answer 18

F2

Question 19

gold

Answer 19

Au

Question 20

helium

Answer 20

He

Question 21

hydrogen

Answer 21

H2

Question 22

iodine

Answer 22

I2

Question 23

iron

Answer 23

Fe

Question 24

lead

Answer 24

Pb

Question 25

lithium

Answer 25

Li

Question 26

magnesium

Answer 26

Mg

Question 27

manganese

Answer 27

Mn

Question 28

mercury

Answer 28

Hg

Question 29

neon

Answer 29

Ne

Question 30

nickel

Answer 30

Ni

Question 31

nitrogen

Answer 31

N2

Question 32

Oxygen

Answer 32

O2

Question 33

phosphorous

Answer 33

P4

Question 34

platinum

Answer 34

Pt

Question 35

potassium

Answer 35

K

Question 36

silicon

Answer 36

Si

Question 37

silver

Answer 37

Ag

Question 38

sodium

Answer 38

Na

Question 39

sulfur

Answer 39

S8

Question 40

tin

Answer 40

Sn

Question 41

titanium

Answer 41

Ti

Question 42

zinc

Answer 42

Zn

Question 43

ammonia

Answer 43

NH3

Question 44

calcium carbonate

Answer 44

CaCO3

Question 45

carbon monoxide

Answer 45

CO

Question 46

carbon dioxide

Answer 46

CO2

Question 47

copper sulfate

Answer 47

CuSO4

Question 48

hydrochloric acid

Answer 48

HCl

Question 49

methane

Answer 49

CH4

Question 50

nitric acid

Answer 50

HNO3

Question 51

nitrogen monoxide

Answer 51

NO

Question 52

nitrogen dioxide

Answer 52

NO2

Question 53

sodium chloride

Answer 53

NaCl

Question 54

sodium hydroxide

Answer 54

NaOH

Question 55

sulfur dioxide

Answer 55

SO2

Question 56

sulfuric acid

Answer 56

H2SO4

Question 57

water

Answer 57

H2O