Period (periodic table) facts for kids
A period in the periodic table is like a horizontal row of elements. Think of the periodic table as a big chart that organizes all the known chemical elements. Each row helps us understand how elements change as their atomic numbers increase.
The elements in a period are arranged by their atomic numbers, which means the number of protons in their atoms. As you move from left to right across a period, the atomic number goes up by one for each element.
Elements on the left side of a period are usually very metallic, like sodium or calcium. As you move to the right, the elements become less metallic and more nonmetallic, like oxygen or chlorine.
The first period has only 2 elements. The second and third periods each have 8 elements. The fourth and fifth periods each have 18 elements. The sixth and seventh periods each have 32 elements because they include the special f-block elements.
The Periodic Table Periods
Here is the standard periodic table, showing how elements are organized into periods and groups.
Group → | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | ||
Period ↓ | ||||||||||||||||||||
1 | 1 H |
2 He |
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2 | 3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne |
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3 | 11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar |
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4 | 19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr |
||
5 | 37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe |
||
6 | 55 Cs |
56 Ba |
* Lanthanides |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn |
||
7 | 87 Fr |
88 Ra |
*Actinides |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Nh |
114 Fl |
115 Mc |
116 Lv |
117 Ts |
118 Og |
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8 | 119 Uue |
120 Ubn |
*Superactinides |
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* Lanthanide Series | 57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu |
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** Actinide Series | 89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr |
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** Superactinide Series | 121 Ubu |
122 Ubb |
123 Ubt |
124 Ubq |
125 Ubp |
126 Ubh |
127 Ubs |
128 Ubo |
129 Ube |
130 Utn |
131 Utu |
132 Utb |
- Chemical Series of the Periodic Table
This section explains the different types of elements you see in the table, based on their properties and where they are located.
- State at standard temperature and pressure
The color of the number (atomic number) above the element symbol shows what state the element is in at normal room temperature and pressure.
- those in blue are gases
- those in green are liquids
- those in black are solid