nonmetals

1

H1.01

Hydrogen

2

He4.00Helium

3

Li6.94Lithium

11

Na22.99Soduim

19

K39.10

Potassium

37

Rb85.47Rubidium

55

Cs132.91Caesuim

87

Fr(223)

Francium

4

Be9.01

Beryllium

12

Mg24.31

Magnesium

5

B10.81Boron

13

Al26.98

Aluminum

6

C12.01Carbon

14

Si28.09Silicon

7

N14.01Nitrogen

15

P30.97

Phosphorus

8

O16.00Oxygen

16

S32.07Sulpher

9

F19.00Fluorine

17

Cl35.45Chlorine

9

Ne20.18

Neon

18

Ar39.95Argon

20

Ca40.08Calcium

38

Sr87.62Strontium

56

Ba137.33

Barium

88

Ra226.03

Radium

105

Db(262)Dubnium

22

Ti47.88Titanium

40

Zr91.22

Zirconium

72

Hf178.49Hafnium

57

La138.91Lanthanum

89

Ac227.03Actinium

58

Ce140.12

Cerium

60

Nd144.24

Neodymium

92

U238.03Uranium

61

Pm(145)

Promethium

93

Np237.05Neptunium

62

Sm150.4

Samarium

94

Pu(244)

Plutonium

63

Eu151.96Europium

95

Am(243)

Americum

64

Gd157.25Gadolinium

96

Cm(247)Curium

65

Tb158.93Terbium

103

Lr(260)

Lawrencium

66

Dy162.50

Dysprosium

97

Bk(247)

Berkelium

67

Ho164.93Holmium

98

Cf(251)

Californium

68

Er167.26

Erbium

99

Es(252)

Einstienium

69

Tm168.93Thulium

100

Fm(257)Fermium

70

Yb173.04Ytterbium

101

Md(258)

Mendelevium

71

Lu174.97Lutetium

102

No(259)

Nobelium

90

Th232.04Thorium

59

Pr140.91

Praseodymium

91

Pa231.04

Protactinium

23

V50.94

Vanadium

41

Nb92.91Niobium

73

Ta180.94Tantalum

106

Sg(263)

Seaborgium

24

Cr52.00

Chromium

42

Mo95.94

Molybdenum

74

W183.85Tungsten

107

Bh(262)Bohrium

25

Mn54.95

Manganese

43

Tc(98)

Technetium

75

Re186.21Rhenium

108

Hs(265)Hassium

26

Fe55.85

Iron

44

Ru101.87Ruthenium

76

Os190.23Osmium

109

Mt(266)

Meitnerium

27

Co58.93Cobalt

45

Rh102.91Rhodium

77

Ir192.22

Iridium

110

(269)

111

(272)

112

(277)

114

(281)

116

(289)

118

(293)

28

Ni58.70Nickel

46

Pd106.4

Palladium

78

Pt195.08Platinum

29

Cu63.55Copper

47

Ag107.87

Silver

79

Au196.97

Gold

30

Zn65.39

Zinc

48

Cd112.41Cadmium

80

Hg200.59Mercury

31

Ga69.72Gallium

49

In114.82

Indium

81

Tl204.38Thallium

32

Ge72.61

Germanium

50

Sn118.71

Tin

82

Pb207.2

Lead

33

As74.92Arsenic

51

Sb121.74Antimony

83

Bi208.98Bismuth

34

Se78.96Selenium

52

Te127.60Tellurium

84

Po(209)

Polonium

35

Br79.90Bromine

53

I126.90

Iodine

85

At(210)Astatine

36

Kr83.80Krypton

54

Xe131.29

Xenon

86

Rn(222)Radon

104

Rf(261)

Rutherfordium

21

Sc44.96

Scandium

39

Y88.91Yttrium

Lanthanideseries

(see below)

Actinideseries

(see below)

transition metals

Period1

alkalimetals

IA

rare earth elements – Lanthanideseries

Actinideseries

noble gasses

O

alkaline earth

metalsIIA IIIA IVA VA VIA VIIA

IIIB IVB VB VIB VIIB VIII IB IB

Period2

Period3

Period4

Period5

Period6

Period7

CHEMICAL DEFENCE

Borrowing some one else’s defence

Armed and dangerous

The stayput stonefish

Photo: Larisa Vanstien

What’s in venom?Photo: Clay Bryce

Anemonefish have a ‘symbiotic’ or mutually beneficial relationship with anemones – they use the anemone for protection against predators and in return keep away intruders and keep the anemone free from parasites. Anemonefish can survive amongst the anemone’s stinging tentacles – which paralyse other fish – by producing a mucous that helps to resist the anemone’s venom. Then over a period of time, which can be several minutes to a few hours, the fish performs a ‘dance’ that involves more and more contact with the anemone, until it becomes immune to the stings.

Venom consists of a mixture of proteins that play with critical bodily funtions (such as blood pressure, heartbeat, nerve and muscle activity, and blood clotting), and can cause pain, blisters, fever, convulsions, breathing difficulties and even death in humans. For example, stingray venom contains enzymes which breakdown and kill cells, as well as the neurotransmitter serotonin, which causes muscle contractions. Should you be unlucky enough to be stung by a venomous fish, immerse or wash the sting area in hot water to ‘denature’ (break down) the proteins and seek medical assistance.

You are what you eat

Photo: Larisa Vanstien

With the existence of many predators in the environment, aquatic animals have developed an amazing variety of defence mechanisms. These include hard exteriors, disguise and camouflage, schooling behaviour, hiding or escaping, and body shapes that are difficult to attack. Spines and barbs are also very common, and many species have taken this form of protection one step further by including venom within the spines – making chemical defence another safeguard against attack.

Venom versus poison

Sleep tight

Photo: Aengus Moran

Going off like a neutron bombBoxfish are also known as ‘Neutron Bomb’ fish. This fish usually goes about its business undisturbed by predators because of its bright colours, which act as a warning, and its scales that have developed into an extremely rigid armour. But if those defences fail, the boxfish secretes a toxin through its pores that can wipe out anything in close proximity to it. To protect itself from its own toxin, the boxfish releases the toxin as it quickly leaves the area.

Biting off more than you can chew

Photo: Henrique Kwong

Most ‘nudibranchs’ or sea slugs have the remarkable ability to absorb the toxins and ‘nematocysts’ (stinging cells) of their prey and transfer them harmlessly to the tips of their own tentacles. These assimilated poisons and ‘harpoons’ are then used to defend the nudibranch from its own predators. This is why many sea slugs are so brightly coloured – a warning that they are unsafe to eat.

Pufferfish have a surprise for predators – they can inflate themselves to a size that is too big to swallow. On top of this, they produce a highly lethal toxin called ‘tetrodotoxin’ – present in the fishes’ skin, flesh and internal organs – that is approximately 1,200 times deadlier than cyanide! Pets have died from eating blowfish (a type of pufferfish) washed up on beaches or left behind by fishers.

If a stingray’s ‘barb’ gets broken off as it defends itself, the stingray’s will grow a new one.

A master of disguise, the stone fish is a very inactive predator – lying still on the bottom, looking like an algae-covered rock, waiting to gulp prey into its huge mouth. But if disturbed, frightened or provoked, it will erect the spines along its back to jab enemies with what is the most deadly venom of any fish in the world! Stonefish have control over whether to shoot its venom, unlike other species (such as the lionfish) that can’t release venom unless something pushes against their spines.

Stone fish venom delivery mechanism: A protective sheath blocks the opening. As pressure is applied, the venom seal breaks and a spine is bared. The sheath is punctured, freeing the opening, and the venom is released. The gland is destroyed by the pressure, but will regenerate and be recharged with venom within a couple of weeks.

SpineVenom gland

Protective Sheath

Blocked gland Pressure from victim

Pressure from victim

Pressure from victim

Destroyed gland and crushed sheath

Opening

Gland clear

Crushed sheath

Discharged venom

Venom duct

Compressed venom gland

Venomous fish (such as scorpionfish, stonefish, stingrays and cobbler) deliver their venom by means of a bite or sting, often through injection. Venom is typically produced in organs specialised for the purpose.

Poisonous fish (such as pufferfish and boxfish) are harmful when eaten or touched, with the poison usually absorbed internally or via the skin. The poison tends to be distributed over a large part of the body of the fish producing it.

Toxins describe a biologically-produced poison or venom, that is, the harmful substance is produced by the living cells of the organism.

Fish have a keen sense of smell and can detect minute changes in water chemistry. Some members of the parrotfish family secrete a mucous ‘cocoon’ around themselves when they rest or sleep. This cocoon acts as a chemical shield, masking any scent that they give off and preventing predators like moray eels from finding the parrotfish by smell. Baldchin groper are thought to use this same defence mechanism.

Close behind the stonefish in ‘poison-power’ is the lionfish (also called butterfly cod, fire cod or red firefish), with its long, colourful, fins and fin spines. This decoration may be used for camouflage or possibly to advertise the lionfish’s deadly poison, which is injected by the spines. The toxin is based upon the lionfish’s diet, much in the same way as nudibranchs use the toxic compounds produced by their prey as part of their own defence.

Photo: Sandy Clarke

There have been anecdotal reports of osteoarthritis sufferers experiencing improved mobility and reduction in joint pain following ‘envenomation’ from stonefish. The responsible agent has not yet been identified.

Some anemones release a chemical ‘perfume’ to attract anemonefish to them.

In Japan, fish from the family Tetraodontidae (which includes well over 100 species of toadfish and pufferfish) are known as ‘fugu’ and are considered a delicacy. Young chefs spend years learning how to prepare fugu. However, each year, a few people still die from eating poorly-prepared fugu dishes.

Perfume