1.13. A Few of the Elements in Group 13, 14, and 15

Learning check

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The boron, carbon, and nitrogen groups are in group 13, 14, and 15.

The boron group

Three valence electrons

Example: The electron configuration for boron, ₅B:

	K	L
5p⁺	2e^–	3e^–

Boron, B

A metalloid

Has some metallic properties, but not all.

Boron.

Borax crystals.

Found in nature as borax, Na₂B₄O₇.
Uses

Glass
Ceramics
(Abrasive) detergents

Boric acid, H₃BO₄

Weak acid

Uses
- DNA buffer
- Flame retardant

Boric acid is used in DNA buffer solutions.

Aluminum, Al

Aluminum has many uses because it is light and durable.

Aluminum may be used in aircraft, …

… aluminum pans, …

… and soda cans.

Aluminium is passivated by a very hard and air-tight oxide layer:

4Al + 3O₂ → 2Al₂O₃

Gallium, Ga

Low melting point, 29.8 °C.

Used in LED lamps.

The carbon group

Four valence electrons

Example: The electron configuration for carbon, ₆C:

	K	L
5p⁺	2e^–	4e^–

Carbon in five different forms

Ethanol, an organical compound.

Graphite.

Diamond structure.

Buckminster fullerene ("Buckyball", "soccer-carbon").

Carbon nanotube.

Graphene.

The Nobel prize in physics 2010.

Silicon, Si

A metalloid.

Second most common element in the earth’s crust.

Quartz mineral: Silicon dioxide, SiO₂.

Used in glass and electronics.

Paving stone made of granite, which contains quartz mineral.

The transistors in the integrated circuit (microchip) are made of silicon.

Tin, Sn

Tin is a metal.

Uses:

Alloy with copper → bronze
Tin casting
Tin plating (corrosion protection)

Tin soldier.

Glass decanters.

Lead, Pb

Heavy metal, poisonus.

Plumber = someone who works with pipes (made of lead, lat. plumbum).

Uses: Ammunition, protection against radiation (and exclusive glass decanters).

The nitrogen group (pnictogens)

Five valence electrons

Example: The electron configuration for nitrogen, ₇N:

	K	L
5p⁺	2e^–	5e^–

Nitrogen, N

Air; 78 % nitrogen gas, N₂(g)

Inert.
Reacts with oxygen at high temperatures, nitrogen oxides form.
Converted to ammonia, NH₃, by nitrogen-fixating bacteria.

Important part of DNA and proteins.

Phosphorus, P

Exists in a few different forms, for example:

White phosphorus, P₄
Red phosphorus in the match boxes’ striking surface

When combusted, forms phosphates, PO\(_4^{3-}\).

Also important part of DNA. Also in phospholipids, which make up biological membranes.

Arsenic, As

Metalloid

Arsenic poisoning (even lethal):

Arsenic-containing bedrock, deep wells.
Problem in e.g. Bangladesh!

A model of a DNA molecule. The blue marbles represent nitrogen atoms and the yellow marbles phosphorus atoms.