# Periodic Table with Atomic Mass URL: https://sciencestruck.com/chemistry/periodic-table-with-atomic-mass Category: Chemistry Published: 2009-12-03T06:26:00 Updated: 2009-12-03T06:26:00 The periodic table provides us with a comprehensive view of the various elements. Along with atomic mass and atomic number values, this table helps us to understand the various properties, abbreviations, and names of all the elements present in nature. The following article will help you to gain more information about the same. The periodic table is one of the most important points of reference in the branch of chemistry, and is often known as the Bible of chemical sciences. The elements arranged in the periodic table are great help to scientists, chemists, scholars, researchers, and even students in understanding their various properties and characteristics at a glance. These elements are arranged in rows and columns - left to right and top to bottom. They follow a pattern, i.e., in an increasing order of the atomic number. **Dmitri Mendeleev**, a Russian chemist, is credited as the first person to invent the periodic table in 1869. There were many versions introduced before _Mendeleev’s table_, but he was the one who illustrated the recurring periodic trends in the elemental properties. Mendeleev found out that 65 elements that were known in his time, could be arranged in a grid. He arranged the elements in his table on the basis of the following points: - He positioned element with higher atomic weights on the left side. - The ones with similar properties were kept in the same column. He got a table with gaps and spaces, which meant that there were further elements yet to be discovered. It was Mendeleev, who predicted undiscovered elements like _eka-silicon_ (as he found a gap between silicon and tin), today known as _germanium_, _gallium_, today called aluminum, and _eka-boron_, known as scandium. With these breakthroughs, Mendeleev could not move further as the Rutherford-Bohr model of the atom was yet to be discovered. After about four decades, Henry Moseley in 1913 showed the atomic number (charge) and not the atomic weight, as proposed by Mendeleev, as the fundamental chemical property of any element. With this knowledge, he was able to predict the presence of new elements. Thus, the elements are arranged in the order of increasing atomic number (Z) left to right across the table. The vertical rows are known as groups and the horizontal rows are known as periods. The alkali earth metals are found in group one, whereas the second group contains alkaline earth metals. Both **1A** and **2A** contain the _s-block_ elements. They contain the same number of outer electrons, and thus show similar chemical properties. The groups are present in the following order: **3B**, **4B**, **5B**, **6B**, **7B**, **8B**, **1B**, and **2B** contain transition metals or the _d-block_ elements. They have similar chemical properties like production of colored compounds and variable valency. They often act as catalysts. The groups **3A**, **4A**, **5A**, **6A** and **7A** consist of _p-block_ elements. The **8A** group contains noble gases. The inner transition or _f-block_ elements are placed under the transition ones in a separate table. These rare earth elements are divided into lanthanides (elements 58 - 71) and actinides (elements 90 - 103). They are found in very minute quantities naturally. The ones with atomic numbers higher than 92 are not found naturally, and are produced artificially in nuclear reactors and particle accelerators. ### Atomic Mass It is defined as the average mass of atoms of an element, which is calculated with the help of relative abundance of isotopes of a naturally occurring element. For example, the atomic mass of hydrogen is 1.0079 and carbon is 12.011. ### Atomic Number Atomic number is defined as the number of protons in an element. For example, the atomic number of hydrogen, carbon, and oxygen is 1, 6, and 8, respectively. The chemical behavior of the elements is determined by the number of protons. ### Atomic Symbol The abbreviation or one/two letters that represent an element is called the atomic symbol. These are the truncated Latin names of the element. Periodic Table _s-block_ Transition Elements _d- block_ _p-block_ Nobel Element Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 1 H 1.0079 2 [He](https://sciencestruck.com/chemistry/interesting-facts-about-helium "Helium") 4.0026 2 3 Li 6.941 4 Be 9.0122 5 B 10.811 6 C 12.011 7 N 14.007 8 O 15.999 9 F 18.998 10 Ne 20.180 3 11 Na 22.990 12 Mg 24.305 13 Al 26.982 14 [Si](https://sciencestruck.com/chemistry/silicon-element "Silicon") 28.086 15 P 30.974 16 S 32.066 17 Cl 35.453 18 Ar 39.948 4 19 K 39.098 20 Ca 40.078 21 Sc 44.956 22 [Ti](https://sciencestruck.com/chemistry/titanium-element "Titanium") 47.867 23 V 50.942 24 Cr 51.996 25 Mn 54.938 26 Fe 55.845 27 Co 58.933 28 Ni 58.693 29 Cu 63.546 30 Zn 65.409 31 Ga 69.723 32 Ge 72.64 33 As 74.922 34 Se 78.96 35 Br 79.904 36 Kr 83.798 5 37 Rb 85.468 38 Sr 87.62 39 Y 88.906 40 Zr 91.224 41 Nb 92.906 42 Mo 95.94 43 Tc (98) 44 Ru 101.07 45 Rh 102.91 46 Pd 106.42 47 Ag 107.87 48 Cd 112.41 49 In 114.82 50 [Sn](https://sciencestruck.com/science-facts/interesting-facts-about-tin "Tin") 118.71 51 Sb 121.76 52 Te 127.60 53 I 126.90 54 Xe 131.29 6 55 Cs 132.91 56 Ba 137.33 57 - 71 La-Lu 72 Hf 178.49 73 Ta 180.95 74 W 183.84 75 Re 186.21 76 Os 190.23 77 Ir 192.22 78 Pt 195.08 79 Au 196.97 80 Hg 200.59 81 Tl 204.38 82 Pb 207.2 83 Bi 208.98 84 Po (209) 85 At (210) 86 Rn (222) 7 87 Fr (223) 88 Ra (226) 89 -103 Ac-Lr 104 Rf (261) 105 Db (262) 106 Sg (266) 107 Bh (264) 108 Hs (277) 109 Mt (268) 110 Ds (281) 111 Rg (272) 112 Cn (277) Lanthanide 57 La 138.91 58 Ce 140.12 59 Pr 140.91 60 Nd 144.24 61 Pm (145) 62 Sm 150.36 63 Eu 151.96 64 Gd 157.25 65 Tb 158.93 66 Dy 162.50 67 Ho 164.93 68 Er 167.26 69 Tm 168.93 70 Yb 173.04 71 Lu 174.97 Actinide 89 Ac (227) 90 Th 232.04 91 Pa 231.04 92 U 238.03 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) Key for the Periodic Table Alkali Metals Alkaline Earth Metals Lanthinides Actinides Transition Metals Poor Metals Other Metals Nobel Gases Metalloids Unknown Chemical Properties