What is Boiling Point?

Boiling point is the temperature at which the pressure exerted by the surroundings on a liquid is equal to the pressure exerted by the liquid’s vapour; the addition of heat results in the transformation of the liquid into its vapour without raising the temperature.

A liquid partially vaporises into the space above it at any temperature until the pressure exerted by the vapour reaches a characteristic value known as the liquid’s vapour pressure at that temperature. The vapour pressure rises as the temperature rises; at the boiling point, bubbles of vapour form within the liquid and rise to the surface.

A liquid’s boiling point varies with applied pressure; the normal boiling point is the temperature at which the vapour pressure equals the standard sea-level atmospheric pressure (760 mm of mercury). Water boils at 100° C (212° F) at sea level. The boiling point temperature is lower at higher altitudes.

Factors affecting Boiling
Boiling Point Trends
Relationship Between Atomic Number and Boiling Point
Boiling Point Table
Frequently Asked Questions – FAQs

Factors Affecting Boiling

The boiling point of a liquid is affected by-

Temperature
Atmospheric pressure
Liquid’s vapour pressure.

Boiling will begin when the atmospheric pressure equals the vapour pressure of the liquid.

Boiling Point Trends

The boiling points of different groups show different trends.

The boiling points of Groups 1 and 2 decrease as you move down the group.
The boiling points of transition metals generally increase as you move down the group, but they decrease for the zinc family.
The boiling points of the boron and carbon families (Groups 13 and 14) decrease as you move down the group.
The boiling point of the nitrogen, oxygen, and fluorine families (Groups 15, 16, and 17) tend to increase.
The boiling points of noble gases (Group 18) decrease as they move down the group.

These phenomena can be explained in terms of the forces that hold the elements together. Metallic bonding interaction (electron-sharing) becomes more difficult as the elements get larger (toward the bottom of the table), causing the forces holding them together to weaken. However, as you move down the table, polarizability and van der Waals interactions predominate. Since larger atoms are more polarizable, they have stronger intermolecular forces and thus higher melting and boiling points.

Relationship Between Atomic Number and Boiling Point

The boiling points increase as you move down the group because the number of electrons increases, as does the radius of the atom. The greater the number of electrons and the greater the distance over which they can move, the greater the possibility of temporary dipoles and, consequently, the greater the dispersion forces.
Also, when there are more electrons around the nucleus, creating a stronger negatively-charged force. The boiling point rises as the forces become stronger. The boiling points of nonmetals are typically low.

Boiling Point Table

Element Atomic Number	Element Symbol	Element Name	Element Boiling Point
1	H	Hydrogen	-252.87 °C
2	He	Helium	-268.93 °C
3	Li	Lithium	1342 °C
4	Be	Beryllium	2470 °C
5	B	Boron	4000 °C
6	C	Carbon	4027 °C
7	N	Nitrogen	-195.79 °C
8	O	Oxygen	-182.9 °C
9	F	Fluorine	-188.12 °C
10	Ne	Neon	-246.08 °C
11	Na	Sodium	883 °C
12	Mg	Magnesium	1090 °C
13	Al	Aluminium	2519 °C
14	Si	Silicon	2.9×103 °C
15	P	Phosphorus	280.5 °C
16	S	Sulfur	444.72 °C
17	Cl	Chlorine	-34.04 °C
18	Ar	Argon	-185.8 °C
19	K	Potassium	759 °C
20	Ca	Calcium	1484 °C
21	Sc	Scandium	2830 °C
22	Ti	Titanium	3287 °C
23	V	Vanadium	3407 °C
24	Cr	Chromium	2671 °C
25	Mn	Manganese	2061 °C
26	Fe	Iron	2861 °C
27	Co	Cobalt	2927 °C
28	Ni	Nickel	2913 °C
29	Cu	Copper	2927 °C
30	Zn	Zinc	907 °C
31	Ga	Gallium	2204 °C
32	Ge	Germanium	2820 °C
33	As	Arsenic	614 °C
34	Se	Selenium	685 °C
35	Br	Bromine	59 °C
36	Kr	Krypton	-153.22 °C
37	Rb	Rubidium	688 °C
38	Sr	Strontium	1382 °C
39	Y	Yttrium	3345 °C
40	Zr	Zirconium	4409 °C
41	Nb	Niobium	4744 °C
42	Mo	Molybdenum	4639 °C
43	Tc	Technetium	4265 °C
44	Ru	Ruthenium	4150 °C
45	Rh	Rhodium	3695 °C
46	Pd	Palladium	2963 °C
47	Ag	Silver	2162 °C
48	Cd	Cadmium	767 °C
49	In	Indium	2072 °C
50	Sn	Tin	2602 °C
51	Sb	Antimony	1587 °C
52	Te	Tellurium	988 °C
53	I	Iodine	184.3 °C
54	Xe	Xenon	-108 °C
55	Cs	Cesium	671 °C
56	Ba	Barium	1870 °C
57	La	Lanthanum	3464 °C
58	Ce	Cerium	3360 °C
59	Pr	Praseodymium	3290 °C
60	Nd	Neodymium	3.1×103 °C
61	Pm	Promethium	3×103 °C
62	Sm	Samarium	1803 °C
63	Eu	Europium	1527 °C
64	Gd	Gadolinium	3250 °C
65	Tb	Terbium	3230 °C
66	Dy	Dysprosium	2567 °C
67	Ho	Holmium	2700 °C
68	Er	Erbium	2868 °C
69	Tm	Thulium	1950 °C
70	Yb	Ytterbium	1196 °C
71	Lu	Lutetium	3402 °C
72	Hf	Hafnium	4603 °C
73	Ta	Tantalum	5458 °C
74	W	Tungsten	5555 °C
75	Re	Rhenium	5596 °C
76	Os	Osmium	5012 °C
77	Ir	Iridium	4428 °C
78	Pt	Platinum	3825 °C
79	Au	Gold	2856 °C
80	Hg	Mercury	356.73 °C
81	Tl	Thallium	1473 °C
82	Pb	Lead	1749 °C
83	Bi	Bismuth	1564 °C
84	Po	Polonium	962 °C
85	At	Astatine	N/A
86	Rn	Radon	-61.7 °C
87	Fr	Francium	N/A
88	Ra	Radium	1737 °C
89	Ac	Actinium	3200 °C
90	Th	Thorium	4820 °C
91	Pa	Protactinium	4000 °C
92	U	Uranium	3927 °C
93	Np	Neptunium	4×103 °C
94	Pu	Plutonium	3230 °C
95	Am	Americium	2011 °C
96	Cm	Curium	3110 °C

Frequently Asked Questions on Why Does More Electrons Increase Boiling Point

What factors influence boiling point?

The boiling point of a liquid is affected by temperature, atmospheric pressure, and the liquid’s vapour pressure.

Does the boiling point increase as one moves down a column?

When going down a column, there is no simple way to identify the trend for boiling points. Some groups increase as you move down a column, while others decrease, and still others show no trend. This is due to the fact that as electron – electron repulsion decreases, so does the boiling point.

Why would the boiling point rise as the number of electrons is increased?

The boiling points increase because the number of electrons increases, as does the radius of the atom. The greater the number of electrons and the greater the distance over which they can move, the greater the possibility of temporary dipoles and, consequently, the greater the dispersion forces.

Is a higher melting point associated with more electrons?

The melting point rises as the atomic number of elements rises because there are more electrons surrounding the nucleus, creating a stronger negatively charged force. The melting point rises as the forces become stronger.

Why do Lighter elements have low boiling points?

Since noble gases have a weak interatomic force, they have very low melting and boiling points.