Boron family: Group 13 elements, properties and characteristics (2023)

What is the boron family?

The boron family includes the semimetal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In) and thallium (Tl). Boron is the fifth element in the periodic table (Z=5) and is found in Group 13. It is classified as a metalloid due to its properties that reflect a combination of metals and non-metals.

Boron family: Group 13 elements, properties and characteristics (1)

These are the chemical elements that are part of group 13 in the p table of the periodic table. They are collectively referred to as the boron group. They are characterized by having three valence electrons. It is mainly composed of 6 elements:

Bor (B)- It's a semi-metal. It is quite rare non-metal. It is extremely hard and black in color. It occurs because subatomic particles created by natural radioactivity disturb the nuclei.

Aluminum (IA)- is the third most abundant element in the Earth's crust (about 8.3%). It is considered a safe element and does not contain any toxicity.

Gallium (Ga)- is found in abundance on earth. It is also used in semiconductors. They are considered eco-friendly. It also has the ability to increase metabolism due to its ability to bind iron proteins.

Indian (In)- it's the 61stmost common element in the Earth's crust. It is mainly used to stimulate the metabolism of the human body.

(Video) Periodic Table Part 4: Boron Group (B, Al, Ga, In, Tl, Nh)

Tálio (Tl) - occurs in moderate amounts. It is highly toxic as it seems to affect vital parts of the body and is mainly used as a pesticide.

Niônio (Nh)-Its traces are not found on Earth and are considered a synthetic element.

The key point about P-block elements is that their last electron enters the outermost p orbital. In all six groups there is a similarity in their electronic configuration, i. H. in general, the electron configuration of the valence shell is ns2np1-6.

Read too: Periodic properties of elements

boron family density



Aluminum (Al)

Gallium (Ga)

indium (inches)

Thalio (TL)







In general, the density increases in the group, but as we can see there is a large increase in density from Al to Ga, as gallium has D electrons, which have the least shielding effect due to the decrease in atomic size, the increase in volume it is also comparatively smaller and therefore the density increases, as the density is inversely proportional to the volume.

The same reason applies to In and Tl, since the f electron, together with the already existing d electrons, due to which the atomic size decreases, also decreases in volume, resulting in an increase in density.

(Video) Boron Group- Group 13-Periodic Table

melting point and boiling point







melting point/K






boiling point/K






In general, melting and boiling points increase down the group, but there is an exception in group 13, as the melting point of boron (2352 K) is exceptionally high, as the structure of boron consists of a crystalline structure denoted as becomes„Ikosaeder", meaning a 20-sided polygon that is not easily broken, and on the other hand, the melting point of gallium (303 k) is the lowest. In fact, gallium exists as a liquid in summer and also has a high boiling point. For this reason, gallium is used to measure high temperatures. The difference is in the structure, as most of the time it looks like adiatomicMolecule.














It is the tendency of an atom to attract a shared pair of electrons. It essentially depends on the size of the atom and the electron. In group 13, the electrons are equal, that is, 3 (valence electrons) in the outermost shell, but the atomic size is not equal, because here the electronegativity increases towards aluminum, the electronic configuration due to the presence of d and f electrons , which increases the size by increasing, but at the same time also increases the nuclear charge, because the d and f electrons have a bad shielding effect. This increases the attraction.

Atomic and ionic rays







atomic radius / pmA












Generally, the radius of the table increases downwards as new layers are added, but here, as we can see, the atomic radius of aluminum is greater than that of gallium due to the addition of gallium, indium and the presence of the 'd' electrons d' and 'f' orbital in thallium. As we know, nuclei are positively charged and electrons are negatively charged, so they attract each other. Here, the charge experienced by the (outermost) valence electrons depends on the shielding effect. The presence of [3d] electrons has a poor shielding effect, as the nuclei attract electrons, thus reducing the gallium radius.

Read too: the atomic radius

(Video) General properties of group 13 element | Boron family | @CatchyStudy

things to remember

  • The boron family includes the semimetal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In) and thallium (Tl). ... Boron is the fifth element in the periodic table (Z=5) and is in group 13. It is classified as a metalloid due to its properties that reflect a combination of metals and non-metals.
  • Pure boron is a dark amorphous powder.
  • Boron has the highest melting point of the metalloids.
  • Boron has the highest boiling point of the metalloids.
  • The isotope boron-10 is used as a neutron absorber in nuclear reactors and is part of emergency shutdown systems.

sample questions

Question: Explain group 13 of the periodic table? (3 points)

Responder:The boron group in group 13 of the periodic table consists of chemical elements consisting of boron, aluminum, gallium, indium, thallium, and nihorium. The common property of the group is that each of the elements has three electrons in the outer shell of the nucleus structure. It is composed of metals, non-metals and even semi-metals.

Questions: Why is it called the Boron family? (2 points)

Responder:It is called the boron family because it is the first element in Group 13 and the only metalloid in the table. Boron is chemically unreactive except at high temperatures. The structure of boron is called an "icosahedron", meaning 20 compact polygons.

Questions: What are the properties of boron? (4 points)

Responder:The following properties are:


  1. Each element in this group has three electrons in the outermost shell, also known as a valence electron.
  2. It is hard and black in color.
  3. it's not metallic
  4. Due to its crystalline structure, it has an exceptionally high melting point.
  5. They have high electrical conductivity.

Questions: What are the uses of Boron? (5 points)

Responder:There are several uses of boron. Some are as follows:

  1. Used in fiberglass and heat-resistant glazing
  2. used in ceramics. Borosilicate glass has great resistance to temperature changes.
  3. used as a rocket fuel igniter.
  4. Used to make bulletproof vests.
  5. used as a mild antiseptic

Questions: What is aluminum used for? (4 points)

Responder:It is the second most used metal in all industries, after iron.

  1. Aluminum is used in power transmission and distribution as it is a better conductor of electricity and is most commonly used in electrical appliances.
  2. Smartphones, tablets, laptops, flat screen TVs and other electronic devices are increasingly using aluminum in their production.
  3. Replace steel and plastic.
  4. used in refrigerators and air conditioners.

Questions: What are the uses of gallium? (4 points)


  1. used in electronic circuits, semiconductors and even LEDs.
  2. They are high-speed semiconductors used to make cell phones, solar panels, etc.
  3. Used in medical thermometers due to its low melting point.
  4. Liquid gallium is used to make mirrors.

Ques: Why is the melting point of the element boron the highest? (3 points)

(Video) P BLOCK ELEMENTS-Group 13- Boron family-physical properties-session 01

Responder:Boron has a high melting point because boron's structure consists of a crystalline structure called "icosahedron", i.e. 20 faceted polygons densely packed together, requiring a large amount of heat to break down. The electronic configuration makes it a different element from the others because of 3 electrons in the outermost shell.

Question: Why does electronegativity increase after aluminum? (2 points)

Responder:The reason electronegativity increases after aluminum is because we see the electron configuration due to the presence of the d and f electrons, which increase the size but at the same time also increase the nuclear charge, as the d and f electrons have a bad shielding effect. This increases the attraction.


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