P Block Elements


P Block Elements
The P block elements have valence electrons in the p orbital.

The p-block elements are a diverse group of elements located on the right side of the periodic table. They get their name from the fact that their valence electrons, or the electrons in the outermost shell, reside in the p orbital. The “p” refers to the principal and azimuthal quantum number 1. These elements display a wide array of properties and are essential in various fields, including biology, environmental science, and materials science.

  • The p-block elements have their valence electrons in the p electron subshell.
  • Their general valence electron configuration is ns2np1-6.
  • There are 36 p-block elements.
  • These elements are those in groups 13, 14, 15, 16, 17, 18 (except not helium).

Location on the Periodic Table

P-block elements are in groups 13 to 18 on the righthand side of the periodic table. They span six element groups (columns), from boron (B) to the noble gases like neon (Ne). These elements include both metals and nonmetals, with metalloids acting as a bridge between the two in terms of properties.

Number of P-Block Elements and Their List

There are 36 p-block elements. The p-block includes the following groups:

Group 13 (Boron Group):

  • Boron (B), Atomic Number 5
  • Aluminum (Al), Atomic Number 13
  • Gallium (Ga), Atomic Number 31
  • Indium (In), Atomic Number 49
  • Thallium (Tl), Atomic Number 81
  • Nihonium (Nh), Atomic Number 113

Group 14 (Carbon Group):

  • Carbon (C), Atomic Number 6
  • Silicon (Si), Atomic Number 14
  • Germanium (Ge), Atomic Number 32
  • Tin (Sn), Atomic Number 50
  • Lead (Pb), Atomic Number 82
  • Flerovium (Fl), Atomic Number 114

Group 15 (Nitrogen Group):

  • Nitrogen (N), Atomic Number 7
  • Phosphorus (P), Atomic Number 15
  • Arsenic (As), Atomic Number 33
  • Antimony (Sb), Atomic Number 51
  • Bismuth (Bi), Atomic Number 83
  • Moscovium (Mc), Atomic Number 115

Group 16 (Oxygen Group):

  • Oxygen (O), Atomic Number 8
  • Sulfur (S), Atomic Number 16
  • Selenium (Se), Atomic Number 34
  • Tellurium (Te), Atomic Number 52
  • Polonium (Po), Atomic Number 84
  • Livermorium (Lv), Atomic Number 116

Group 17 (Halogens):

  • Fluorine (F), Atomic Number 9
  • Chlorine (Cl), Atomic Number 17
  • Bromine (Br), Atomic Number 35
  • Iodine (I), Atomic Number 53
  • Astatine (At), Atomic Number 85
  • Tennessine (Ts), Atomic Number 117

Group 18 (Noble Gases):

  • Neon (Ne), Atomic Number 10
  • Argon (Ar), Atomic Number 18
  • Krypton (Kr), Atomic Number 36
  • Xenon (Xe), Atomic Number 54
  • Radon (Rn), Atomic Number 86
  • Oganesson (Og), Atomic Number 118

Note that helium (He, atomic number 2) is an s-block element and not a p-block element.

Electron Configuration of P-Block Elements

Atoms of the p-block elements have valence electrons in the p electron shell with the general electron configuration of ns2np1-6.

Atomic NumberSymbolElectron Configuration
5B[He] 2s2 2p1
6C[He] 2s2 2p2
7N[He] 2s2 2p3
8O[He] 2s2 2p4
9F[He] 2s2 2p5
10Ne[He] 2s2 2p6
13Al[Ne] 3s2 3p1
14Si[Ne] 3s2 3p2
15P[Ne] 3s2 3p3
16S[Ne] 3s2 3p4
17Cl[Ne] 3s2 3p5
18Ar[Ne] 3s2 3p6
31Ga[Ar] 3d10 4s2 4p1
32Ge[Ar] 3d10 4s2 4p2
33As[Ar] 3d10 4s2 4p3
34Se[Ar] 3d10 4s2 4p4
35Br[Ar] 3d10 4s2 4p5
36Kr[Ar] 3d10 4s2 4p6
49In[Kr] 4d10 5s2 5p1
50Sn[Kr] 4d10 5s2 5p2
51Sb[Kr] 4d10 5s2 5p3
52Te[Kr] 4d10 5s2 5p4
53I[Kr] 4d10 5s2 5p5
54Xe[Kr] 4d10 5s2 5p6
81Tl[Xe] 4f14 5d10 6s2 6p1
82Pb[Xe] 4f14 5d10 6s2 6p2
83Bi[Xe] 4f14 5d10 6s2 6p3
84Po[Xe] 4f14 5d10 6s2 6p4
85At[Xe] 4f14 5d10 6s2 6p5
86Rn[Xe] 4f14 5d10 6s2 6p6
113Nh[Rn] 5f14 6d10 7s2 7p1
114Fl[Rn] 5f14 6d10 7s2 7p2
115Mc[Rn] 5f14 6d10 7s2 7p3
116Lv[Rn] 5f14 6d10 7s2 7p4
117Ts[Rn] 5f14 6d10 7s2 7p5
118Og[Rn] 5f14 6d10 7s2 7p6

Oxidation States

Each group within the p block displays a main oxidation state, but atoms also have other oxidation states. The general electron configuration and oxidation states for each group are:

GroupGeneral Electron ConfigurationMain Oxidation StateOther Oxidation States
13ns2 np1+3+1, -3
14ns2 np2+4-4, +2
15ns2 np3-3+3, +5
16ns2 np4-2+2, +4, +6
17ns2 np5-1+1, +3, +5, +7
18ns2 np60(Rarely +2, +4)

Characteristics

P-block elements share some general characteristics, such as the capacity for forming covalent bonds. Their atoms can either gain or lose electrons. They also display a wide range of oxidation states, which makes them versatile in chemical reactions. Additionally, elements in this block show trends in electronegativity, ionization energy, and atomic size across the period and down the group.

Atomic Size

  • Across a Period (Left to Right): As you move from left to right across a period in the p-block, atomic size generally decreases. This is because as electrons add to the same shell, the increased nuclear charge pulls the electron cloud closer to the nucleus.
  • Down a Group (Top to Bottom): Moving down a group, atomic size increases. Each successive element has an additional electron shell, making the atom larger.

Ionization Energy

  • Across a Period: Ionization energy, the energy required to remove an electron, generally increases across a period. This increase is due to the greater nuclear charge, which more strongly attracts electrons in the outer shell.
  • Down a Group: Ionization energy decreases down a group. The outer electrons are further from the nucleus and less tightly held, so they’re easier to remove.

Electronegativity

  • Across a Period: Electronegativity, the tendency of an atom to attract electrons, generally increases across a period. Elements on the right side of the p-block (like halogens) are more electronegative because they are closer to completing their valence shell.
  • Down a Group: Electronegativity decreases down a group. The increased distance between the nucleus and the valence electrons makes the atomic nucleus less effective at attracting additional electrons.

Metallic Character

  • Across a Period: Metallic character decreases across a period. Elements on the left side (like boron and aluminum) exhibit more metallic properties, such as malleability and electrical conductivity. In contrast, elements towards the right (like oxygen and fluorine) are nonmetallic.
  • Down a Group: Metallic character increases down a group. Elements at the bottom of a group (like thallium) are more metallic than those at the top (like boron).

Reactivity

  • In General: Reactivity varies significantly across the p-block due to the diversity of elements. For instance, the halogens (Group 17) are highly reactive, readily gaining electrons to achieve a stable noble gas configuration. In contrast, the noble gases (Group 18) are generally inert due to their already stable electronic configuration.
  • Toxicity: Here, the p-block elements exhibit significant differences. For instance, nonmetals in the p-block such as oxygen and nitrogen are vital for life, whereas some p-block metals like lead and thallium are toxic.

Oxidation States

  • Variability: P-block elements exhibit a variety of oxidation states. The range of oxidation states increases for elements further down a group and to the right in a period, primarily due to the involvement of d-orbitals in bonding for heavier elements.

Nature of Oxides

  • Across a Period: The nature of oxides changes from acidic to basic across a period. Elements on the left form basic oxides, while those on the right form acidic oxides. For example, aluminum oxide (Al2O3) is amphoteric, silicon dioxide (SiO2) is weakly acidic, and phosphorus pentoxide (P2O5) is strongly acidic.

Uses of P-Block Elements

The p-block elements are important various industries, technologies, and everyday life:

  • Boron (B): Boron is in borosilicate glass for laboratory glassware and cookware. It’s also important in fiberglass and as a dopant in semiconductor manufacturing.
  • Carbon (C): Carbon is essential in organic chemistry and is the basis of all life on Earth. It’s graphite in pencils and as a lubricant and diamond as a gemstone and in cutting tools due to its hardness.
  • Nitrogen (N): Nitrogen is critical in agriculture in fertilizers to promote plant growth. It’s also useful in the production of ammonia and in food preservation.
  • Oxygen (O): Oxygen is essential for respiration in most living organisms. In industry, it plays a role in steelmaking, welding, and as an oxidizer in rocket fuel.
  • Fluorine (F): Fluorine is key in the manufacture of Teflon (used in non-stick cookware) and in refrigerants. Fluoride in toothpaste helps prevent tooth decay.
  • Aluminum (Al): Aluminum is a lightweight metal in aircraft manufacturing, packaging, and the construction industry.
  • Silicon (Si): Silicon is crucial in the electronics industry for semiconductors and integrated circuits. It also finds use in the production of solar cells and as a component in silicone polymers.
  • Phosphorus (P): Phosphorus is key component of fertilizers. It’s also in detergents, pesticides, and matches.
  • Sulfur (S): Sulfur is important the vulcanization of rubber, the manufacture of sulfuric acid, and the production of fungicides and insecticides.
  • Chlorine (Cl): Chlorine is important in water purification, the production of PVC (polyvinyl chloride) for plumbing and electrical cable insulation, and in the manufacture of household cleaning products.
  • Argon (Ar): Argon is an inert shielding gas in welding and in the manufacture of incandescent and fluorescent lighting.
  • Gallium (Ga): Gallium is in semiconductors for high-speed integrated circuits and LEDs.
  • Germanium (Ge): Germanium is in fiber-optic systems, infrared optics, and in solar cell applications.
  • Bromine (Br): Bromine is in fire retardants, in photography, and as a constituent of certain drugs.
  • Krypton (Kr): Krypton is in certain photographic flash lamps and as a filling gas for high-performance lighting.
  • Iodine (I): Iodine is essential in nutrition and is in medical disinfectants and antiseptics. It’s also important in the production of certain dyes and in photography.
  • Xenon (Xe): Xenon finds use in flash lamps, arc lamps for film projection, and in certain types of lasers.
  • Radon (Rn): Radon has limited use in cancer treatment and geological research.

References

  • Bohr, N. (1913). “On the Constitution of Atoms and Molecules, Part II. Systems containing only a Single Nucleus”. Philosophical Magazine. 26: 476–502.
  • Langmuir, Irving (June 1919). “The Arrangement of Electrons in Atoms and Molecules”. Journal of the American Chemical Society. 41 (6): 868–934. doi:10.1021/ja02227a002
  • Scerri, Eric (2020). “Recent attempts to change the periodic table”. Philosophical Transactions of the Royal Society A. 378 (2180). doi:10.1098/rsta.2019.0300
  • Stewart, Philip (April 2010). “Charles Janet: unrecognized genius of the Periodic System”. Foundations of Chemistry. 12: 5–15. doi:10.1007/s10698-008-9062-5