Non metals

The non-metals or non-metallic elements; hydrogen (H), carbon (C), nitrogen (N), oxygen (O), phosphorus (P), sulphur (sulfer) (S), selenium (Se), (Uuo may belong here) and the noble gases form a relatively small group with a step like pattern towards the left-hand side of the periodic table (hydrogen being the odd one out on the right of the table). Non-metals are not strictly defined, but tend to show characteristic properties like poor heat and electrical conductivity, form acidic oxides, dull low lustre and brittle, low densities, low melting points and high electro negativity.
Hydrogen can become metallic when exposed to extremely high pressures. Some allotropes of elements show more pronounced metal, metalloid or non-metal behaviour than others. The element carbon; its diamond allotrope is non-metallic, however the graphite allotrope is electrically conductive showing characteristic more like a metalloid. Phosphorus, and selenium also have allotropes which display borderline behaviour.
Point at or click an element for more information:

Group*** Period

1 IA 1A

2 IIA 2A

3 IIIB 3B

4 IVB 4B

5 VB 5B

6 VIB 6B

7 VIIB 7B

8 VIII 8

9 VIII 8

10 VIII 8

11 IB 1B

12 IIB 2B

13 IIIA 3A

14 IVA 4A

15 VA 5A

16 VIA 6A

17 VIIA 7A

18 VIIIA 8A

1

1 H 1.008

2 He4.003

2

3 Li6.941

4 Be 9.012

5 B10.81

6 C12.01

7 N 14.01

8 O16.00

9 F19.00

10 Ne20.18

3

11 Na 22.99

12 Mg 24.31

13 Al26.98

14 Si28.09

15 P 30.97

16 S32.07

17 Cl35.45

18 Ar39.95

4

19 K 39.10

20 Ca40.08

21 Sc44.96

22 Ti47.88

23 V50.94

24 Cr52.00

25 Mn54.94

26 Fe55.85

27 Co58.47

28 Ni58.69

29 Cu63.55

30 Zn65.39

31 Ga69.72

32 Ge72.59

33 As 74.92

34 Se78.96

35 Br79.90

36 Kr83.80

5

37 Rb85.47

38 Sr87.62

39 Y 88.91

40 Zr91.22

41 Nb92.91

42 Mo95.94

43 Tc(98)

44 Ru101.1

45 Rh102.9

46 Pd106.4

47 Ag107.9

48 Cd112.4

49 In114.8

50 Sn118.7

51 Sb 121.8

52 Te127.6

53 I126.9

54 Xe131.3

6

55 Cs132.9

56 Ba137.3

*

72 Hf178.5

73 Ta180.9

74 W183.9

75 Re186.2

76 Os190.2

77 Ir190.2

78 Pt195.1

79 Au197.0

80 Hg200.5

81 Tl204.4

82 Pb207.2

83 Bi209.0

84 Po(209)

85 At(210)

86 Rn(222)

7

87 Fr(223)

88 Ra(226)

**

104 Rf(261)

105 Db(262)

106 Sg(266)

107 Bh(264)

108 Hs(269)

109 Mt(268)

110 Ds(281)

111 Rg(272)

112 Uub(285)

113 Uut(284)

114 Uuq (289)

115 Uup(288)

116 Uuh(292)

117 Uus()

118 Uuo(294)

Lanthanide Series* (Lanthanoid)

57 La138.9

58 Ce140.1

59 Pr 140.9

60 Nd144.2

61 Pm(145)

62 Sm150.4

63 Eu152.0

64 Gd157.3

65 Tb158.9

66 Dy162.5

67 Ho164.9

68 Er167.3

69 Tm168.9

70 Yb173.0

71 Lu175.0

Actinide Series** (Actinoids)

89 Ac(227)

90 Th232.0

91 Pa(231)

92 U(238)

93 Np(237)

94 Pu(244)

95 Am(243)

96 Cm(247)

97 Bk(247)

98 Cf(251)

99 Es(252)

100 Fm(257)

101 Md(258)

102 No(259)

103 Lr(262)

***Groups are by 3 notation conventions.