Periodic Table Trends- Atomic size, Melting & Boiling Point Trend

The modern periodic table is based on the law that the properties of an element are a periodic function of their atomic number. These properties are related to the electronic configuration of the elements.

We observe a common trend in properties as we move across a period from left to right or down the group. This trend in properties is known as periodic properties.

The important periodic properties are atomic size, metallic character, non-metallic character, ionization potential, electron affinity, and electronegativity.

The modern periodic table is based on the law that the properties of an element are a periodic function of their atomic number. These properties are related to the electronic configuration of the elements.

Periodic Table Trends:

The following trend in periodic properties of elements is observed:

The distance between the centre of the nucleus and the outermost shell of an atom is known as the atomic radius. In a group the atomic size increases due to the addition of shells as we move from one period to another. Across a period the atomic size decreases as the number of shells remain the same while the nuclear charge increases. This leads to the pulling of electrons from the outermost shell towards the nucleus thereby decreasing the size.

The elements which lose electrons to form cations are known as metals. Metallic character increases as we move down the group because the atomic size increases which lead to easy loss of electrons. On the other hand, it decreases across a period as we move from left to right. This happens because there is an increase in nuclear charge which makes it difficult for an atom to lose electrons.

The elements which have a tendency to gain electrons are known as non-metals. The tendency to gain electrons increases on moving across a period due to an increase in the nuclear charge and a decrease in the atomic size.  Hence, non-metallic character increases across a period. As we move down the group the non-metallic character decreases due to an increase in the atomic size.

Ionization potential is defined as the amount of energy required to remove an electron from the outermost shell of a gaseous atom and convert it into a positively charged gaseous ion. The periodic properties in terms of ionization potential increase because the atomic size decreases across a period due to an increase in the nuclear charge. When we move down the group, ionization potential decreases due to the increase in atomic size.

The melting point of an element is basically the energy required to change the state of an element from its solid state to its liquid state. Which essentially implies breaking a few bonds. Thus, higher the stronger the bond between the atoms, the higher will be the melting point. Let us look at the elements in the ascending order of their melting points.

Melting PointElementAtomic Number
-272Helium  (He)2
-259Hydrogen (H)1
-249Neon (Ne)10
-220Fluorine  (F)9
-218Oxygen  (O)8
-210Nitrogen N7
-189Argon Ar18
-157Krypton Kr36
-112Xenon Xe54
-101Chlorine Cl17
-71Radon Rn86
-39Mercury Hg80
-7Bromine Br35
27Francium Fr87
29Cesium Cs55
30Gallium Ga31
39Rubidium Rb37
44Phosphorus P15
64Potassium K19
98Sodium Na11
113Sulphur S16
114Iodine I53
157Indium In49
180Lithium Li3
217Selenium Se34
232Tin Sn50
254Polonium Po84
271Bismuth Bi83
302Astatine At85
303Thallium Tl81
321Cadmium Cd48
327Lead Pb82
420Zinc Zn30
449Tellurium Te52
630Antimony Sb51
639Magnesium Mg12
640Neptunium Np93
640Plutonium Pu94
660Aluminium Al13
700Radium Ra88
725Barium Ba56
769Strontium Sr38
795Cerium Ce58
816.8Arsenic As33
822Europium Eu63
824Ytterbium Yb70
827Nobelium No102
839Calcium Ca20
860Einsteinium Es99
900Californium Cf98
920Lanthanum La57
935Praseodymium Pr59
937Germanium Ge32
962Silver Ag47
986Berkelium Bk97
994Americium Am95
1010Neodymium Nd60
1050Actinium Ac89
1064Gold Au79
1072Samarium Sm62
1083Copper Cu29
1100Promethium Pm61
1132Uranium U92
1245Manganese Mn25
1278Beryllium Be4
1311Gadolinium Gd64
1340Curium Cm96
1360Terbium Tb65
1410Silicon Si14
1412Dysprosium Dy66
1453Nickel Ni28
1470Holmium Ho67
1495Cobalt Co27
1522Erbium Er68
1523Yttrium Y39
1527Fermium Fm100
1535Iron Fe26
1539Scandium Sc21
1545Thulium Tm69
1552Palladium Pd46
1568Protactinium Pa91
1627Lawrencium Lr103
1656Lutetium Lu71
1660Titanium Ti22
1750Thorium Th90
1772Platinum Pt78
1852Zirconium Zr40
1857Chromium Cr24
1890Vanadium V23
1966Rhodium Rh45
2150Hafnium Hf72
2200Technetium Tc43
2250Ruthenium Ru44
2300Boron B5
2410Iridium Ir77
2468Niobium Nb41
2617Molybdenum Mo42
2996Tantalum Ta73
3045Osmium Os76
3180Rhenium Re75
3410Tungsten W74
3500Carbon C6
Mendelevium Md101
Rutherfordium Rf104
Dubnium Db105
Seaborgium  Sg106
Bohrium Bh107
Hassium Hs108
Meitnerium Mt109
Darmstadtium Ds110
Roentgenium Rg111
Copernicium Cn112
Nihonium Nh113
Flerovium Fl114
Moscovium Mc115
Livermorium Lv116
Tennessine Ts117
Oganesson Og118

Just like how the strength of the bonds between atoms affect the Melting Point, the boiling point depends on the heat energy required to create a transition from liquid to gaseous state. Have a look at this table with the elements of the periodic table arranged in order of increasing boiling points.

Boiling 
point
ElementSymbolAtomic number
-269HeliumHe2
-253HydrogenH1
-246NeonNe10
-196NitrogenN7
-188FluorineF9
-186ArgonAr18
-183OxygenO8
-153KryptonKr36
-108XenonXe54
-62RadonRn86
-35ChlorineCl17
58.8BromineBr35
184IodineI53
280PhosphorusP15
337AstatineAt85
357MercuryHg80
445SulphurS16
613ArsenicAs33
677FranciumFr87
678CesiumCs55
685SeleniumSe34
688RubidiumRb37
760PotassiumK19
765CadmiumCd48
774PotassiumK19
883SodiumNa11
907ZincZn30
962PoloniumPo84
990TelluriumTe52
1090MagnesiumMg12
1140BariumBa56
1347LithiumLi3
1384StrontiumSr38
1457ThalliumTl81
1466YtterbiumYb70
1484CalciumCa20
1560BismuthBi83
1597EuropiumEu63
1727ThuliumTm69
1737RadiumRa88
1740LeadPb82
1750AntimonySb51
1900SamariumSm62
1962ManganeseMn25
2000IndiumIn49
2212SilverAg47
2270TinSn50
2355SiliconSi14
2403GalliumGa31
2467AluminiumAl13
2510ErbiumEr68
2550BoronB5
2562DysprosiumDy66
2567CopperCu29
2607AmericiumAm95
2672ChromiumCr24
2720HolmiumHo67
2732NickelNi28
2750IronFe26
2807GoldAu79
2830GermaniumGe32
2832ScandiumSc21
2870CobaltCo27
2927PalladiumPd46
2970BerylliumBe4
3000PromethiumPm61
3041TerbiumTb65
3127PraseodymiumPr59
3127NeodymiumNd60
3200ActiniumAc89
3233GadoliniumGd64
3235PlutoniumPu94
3257CeriumCe58
3287TitaniumTi22
3315LutetiumLu71
3337YttriumY39
3380VanadiumV23
3469LanthanumLa57
3727RhodiumRh45
3818UraniumU92
3827PlatinumPt78
3900RutheniumRu44
3902NeptuniumNp93
4377ZirconiumZr40
4527IridiumIr77
4612MolybdenumMo42
4790ThoriumTh90
4827CarbonC6
4877TechnetiumTc43
4927NiobiumNb41
5027OsmiumOs76
5400HafniumHf72
5425TantalumTa73
5627RheniumRe75
5660TungstenW74
 ProtactiniumPa91
 CuriumCm96
 BerkeliumBk97
 CaliforniumCf98
 EinsteiniumEs99
 FermiumFm100
 MendeleviumMd101
 NobeliumNo102
 LawrenciumLr103
 RutherfordiumRf104
 DubniumDb105
 SeaborgiumSg106
 BohriumBh107
 HassiumHs108
 MeitneriumMt109
 DarmstadtiumDs110
 RoentgeniumRg111
 CoperniciumCn112
 NihoniumNh113
 FleroviumFl114
 MoscoviumMs115
 LivermoriumLv116
 TennessineTs117
 OganessonOg118

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.