Aluminium Structure & Characteristics: 25 Quick Facts

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Aluminium is a silvery white and light weight malleable metallic substance. Let us discuss the structure and some relevant characteristics on aluminium briefly.

Aluminium has a crystalline structure with face centered cubic pattern. The single metal atom, aluminium is spherical in shape. It is a p-block element having one electron in 3p orbital. It is a good conductor of heat and electricity due to this free electron in p-orbital.

Let us focus on the structure, lone pairs, valence electrons, solubility, polarity of aluminium in detail.

How to draw aluminium structure?

Lewis structure, a structural representation of any molecule, shows the nonbonding electrons as the electron dots around each of the atom. Let us explain it.

The structure of aluminium contains 13 protons and 14 neutrons which form the positively charged nucleus. 13 electrons are revolving around the nucleus of aluminium to maintain the electrical neutrality.  

These electrons are filled in the different orbitals (s and p) from lower energy to higher energy. For the filling up the orbitals with electrons, Pauli’s exclusion principle, Hund’s multiplicity rule and Aufbau principle must be satisfied.

aluminium structure
Structure of Aluminium.
Image Credit: Wikimedia Commons.

Aluminium Structure Resonance

Resonance is nothing but the delocalization of electron cloud to all over the molecule for gaining extra stability. Let us talk about this.

Drawing of resonance structures is not possible for aluminium as it is a single metal atom. No other atoms are attached with aluminium to share the electron cloud from aluminium. Therefore, electron cloud cannot be delocalized over any other atoms.

Resonance structures can only be possible if aluminium is attached through covalent bonds with other atoms. Then electron cloud of it or any other atom can be delocalized over it or from it.

Aluminium Structure Shape

Shape denotes the respective three-dimensional arrangement of the bonds present in the molecule. Let us give an overview on it.

Aluminium is presented as a spherical shape. The reason behind achieving this shape is the uniform distribution of electron cloud of aluminium. All the single atom attains this spherical shape due to not distortion of electron cloud by any other atom. The lattice structure of aluminium possesses face centered cubic pattern.

If aluminium is bonded with any other atoms and form a covalent compound then shape can be linear, planar, octahedral, TBP or any other except spherical because electron cloud of aluminium will be distorted due to the presence of those neighbouring bonded atoms.

Aluminium Structure Formal Charge

Formal charge is theoretical charge, carried by the individual atom in a molecule. It has a significant role to determine the most stable lewis structure. Let us focus on this.

The formal charge of aluminium is considered to be zero as it is a single unimolecular metal atom having no bond connectivity with other atoms. Formal charge is calculated using the formula = {Total number of valance electrons – number of nonbonding electrons– (number of electrons involved in bond formation/2)}.

Aluminium has no nonbonding electrons as well as the bonding electrons as it does not form any covalent bond with any other atom. Therefore, formal charge of aluminium or any other unimolecular substance will be zero.

Aluminium Structure Angle

Structure angle denotes the angle between the two covalent bonds and one atom between these two bonds. Let us explore this.

The angle in aluminium cannot be determined because it is not attached with any other atoms through covalent bonds. Bond angle can only be determined for any compound having minimum two atoms attached through minimum one bond. For example, the bond angle of <Cl-Al-Cl in AlCl3 is 1200.

Aluminium Structure Octet Rule

Octet rule states that any atom should achieve eight electrons in its valence shell to match with the electron configuration of its nearest noble gas. Let us explain it.

Aluminium does not obey octet rule as it does not form any covalent bond with other atoms. Therefore, it has no scope to achieve eight electrons in its valence shell through the sharing of electron pairs with other atoms.

Aluminium has three electrons in its outer most shell. As it is not attached with any other atoms, it cannot get eight electrons through covalent bond formation. Therefore, octet rule is violated in aluminium.

Aluminium Structure Lone Pairs

The electrons which are not shared with other atoms through covalent bonding, are considered as lone pairs or nonbonding electrons. Let us talk about this.

The number of lone pairs in aluminium is three because the valence electrons of aluminium are regarded as the lone pairs of aluminium. As aluminium is not attached with any atom through covalent bonding, there is no bonding electrons as well as nonbonding electrons in aluminium.

As aluminium is a single unimolecular metal atom, no outer shell electrons are participating in bonding. Therefore, all the valence electrons behave as lone pairs or nonbonding electrons.

Aluminium Valence Electrons

Electrons, associated with the outer most shell of any atom are regarded as valence electrons. Let us explain this.

The total number of valence electrons in aluminium is three. These three electrons come from 3s and 3p orbitals of aluminium (3s2 3p1). It is a p-block element and all the p-block elements have electron configuration ns2 np1-5.

Aluminium can remove these three electrons from its 3p orbital and can achieve a fulfilled electron configuration ([Ne] 3s2). Therefore, aluminium can be present as Al3+.

 Aluminium Hybridization

Hybridization is the concept of mixing of the two atomic orbitals coming from two same or two different atoms. Let us discuss it.

The hybridization of aluminium is not possible because there is no scope of mixing of two atomic orbitals. Aluminium is a unimolecular metal atom. There is no other atom with which the atomic orbital of aluminium can be mixed and a new hybrid orbital will be generated.

The term “hybridization” is always applicable for any compound having minimum two atoms as to generate a new hybrid orbital as mixing of atomic orbitals is mandatory in hybridization.

Aluminium Solubility

Solubility is nothing but the ability to form a solution of any solute. Let us talk about this.

  • Aluminium is soluble in water. It can dissolve in water at the pH range 5.5-6.0.
  • It also gets dissolved in aqua regia (the mixture of HCl and HNO3 in the ratio of 3:1).
  • Aluminium has solubility in hot and concentrated hydrochloric acid in which Al reacts with H2O and evolve H2 gas.
  • Aluminium is also soluble in sodium and potassium hydroxide at room temperature and form aluminates.

Aluminium Uses

Aluminium is one of the most important metals in today’s life. Let us discuss its some significant uses.

  • Aluminium is used in a broad variety of products in different fields including foils, kitchen utensils, aeroplane parts, window frames and many more.
  • Aluminium has uses as alloys with copper, manganese, magnesium, silicon etc.
  • Being a good electrical conductor, it is often used as electrical transmission wires.
  • Because of its strength and light weight, it is also used in architectural applications.

Is aluminium soluble in water?

Solubility in water depends upon the nature of the solvent. Let us explain this in detail.

The solubility of aluminium in pure water is very less. Al can dissolve in water in the pH range 5.5-5.0. The concentration of dissolved aluminium is changed due to depending upon the pH values of water.

Why and how the solubility of aluminium in water is very less?

The solubility of aluminium in water is very less because of the formation of aluminium oxide (Al2O3). Al2O3 creates a layer over the freshly prepared raw aluminium. This is water insoluble. Therefore, metallic aluminium cannot come into the contact of water and it does not get dissolved in water.

Is aluminium a strong electrolyte?

Electrolytes are those which can be dissociated into ion in aqueous solution. Let us talk about this.

Metallic aluminium cannot be an electrolyte as it cannot be dissociated into two oppositely charged ions in aqueous solution. Metallic aluminium is just a single unimolecular substance which cannot be dissociated in water.

Why and how aluminium is not a strong electrolyte?

Aluminium is a non-electrolyte because two oppositely charged ions cannot be produced after dissolving aluminium in water. But AlCl3 becomes a strong electrolyte as it can generate one Al3+ and three Cl– ion after dissociation which can conduct electricity.

Is aluminium acidic or basic?

Acidity and basicity depend upon the nature of the compound as well as the other compound with which it reacts to show acidity or basicity. Let us discuss it in detail.

Aluminium is neither acidic nor basic. It behaves as an amphoteric substance which can act as both the acid and base.

Why aluminium is an amphoteric substance?

  • Aluminium is considered to be an amphoteric substance because it can react both the acid and base.
  • The reaction of aluminium with acid – 2Al (s) + 6HCl (aq) = 2AlCl3 + 3H2.
  • The reaction with the base is – 2Al (s) + 2OH– (aq) + 6H2O (l) = 2Al(OH)4– (aq) + 3H2 (g)

Is aluminium polar or nonpolar?

Polarity or non-polarity depends upon the relative arrangement of the covalent bonds or the separation of two opposite charges. Let us define it.

Aluminium cannot be a polar molecule as it is a single metal atom. There is neither any separation of charge nor any polar covalent bond. Any single atom becomes always nonpolar due to uniform distribution of its electron cloud.

Why and how aluminium is nonpolar?

Aluminium is a nonpolar molecule as its electron cloud cannot be distorted with the presence of another atom. Polarity can only be shown by any compound having minimum two atoms.  For example, one of the compounds of aluminium, AlCl3 shows polarity because of the polar Al-Cl bond.

is aluminium linear?

Being linear is one type of shape of any molecule. Let us talk about this whether aluminium is linear or not.

Aluminium is not linear in shape. It attains spherical shape because of its uniform charge distribution to all over the atom.

Why and how aluminium is not linear?

Aluminium is not linear because it is a unimolecular metal atom. To be a linear, Minimum two atoms are required (a straight line should require minimum two points) and the hybridization of the central atom should be sp. As hybridization is not possible for any unimolecular atom therefore, it cannot attain linear geometry.

Is aluminium magnetic?

Magnetism is defined as the force by which a magnet can attract or repel each other. Let us give an overview on it.

Aluminium is not a magnetic substance as it cannot be attracted by the magnet. It is not a strong metal like iron nickel and magnet can only be attracted by any strong metal.

Why and how aluminium is not magnetic?

Aluminium is not magnetic because it is a paramagnetic substance, not a ferromagnetic or ferrimagnetic substance. It has unpaired electrons but those electrons are not properly oriented as the ferromagnetic compound (iron, nickel etc).

Is aluminium a conductor?

Conductor are those who allows electricity to flow through it. Let us discuss about it in detail.

Aluminium is a very good conductor of both the heat and electricity. It shows high conductance due to the presence of free electrons in its valence shell. Conductance is a parameter which solely depends upon the movement of the free electrons and for this reason metals become good conductors.

Why and how aluminium is a good conductor?

Aluminium is a good conductor because it has free electrons in its valence shell (3p orbital). These free electrons of aluminium are delocalizing through all over the lattice structure of aluminium and shows high conductivity power of heat and electricity.

Is aluminium metallic or non-metallic?

Metallic or non-metallic character defines the ability to lose or accept an electron to become positively or negatively charged species. Let us discuss it.

Aluminium is definitely a metallic substance. Metals can easily donate one or more than one electron to be oxidized. After donating valence electrons, they achieve complete shell electron configuration.

Why and how aluminium is metallic?

Aluminium shows metallic character because it also donates its valence electrons from 3s and 3p orbitals to achieve the full filled electron configuration (1s2 2s2 2p6). After losing three electrons it becomes Al3+. Therefore, metals behave as a good reducing agent like rest of the metals.

Is aluminium a mixture?

Mixture or pure substance defines the presence or absence of any foreign substance with the compound. Let us find out it.

Aluminium is not a mixture, it is a pure substance. It is a unimolecular single metal atom with atomic number 13 and molecular mass 27 g/mol. No other foreign compounds are mixed with aluminium.

Is aluminium brittle?

Metals which will break without significant plastic deformation are defined as brittle substance. Let us comment on it.

Aluminium is not a brittle element rather it shows ductile fracture at all temperatures. Though it is one of the lightest elements in the world, but it is extremely flexible in nature. Aluminium shows ductility because its surface is always covered with the thin but strong layer of oxide film.

Is aluminium crystalline or amorphous?

Crystallinity and amorphous nature define the presence or absence of the particular arrangement of the constituent atoms respectively. Let us explain it.

Aluminium is a crystalline substance. Even most of the metals shows crystallinity due to having highly ordered arrangement of the constituent atoms in their lattice structure.

Why aluminium is a crystalline compound?

Aluminium is definitely a crystalline compound because it has a sharp melting and boiling point. Besides that, it is a metal and most of the metals are crystalline in nature. Amorphous aluminium can only be obtained if liquid aluminium is cooled at the extraordinary rate of 4×1013 K/s.

Is aluminium lighter than steel?

Heavy metals are those metal which have atomic number greater than 20 and atomic density above 5 g/cm3. Other metals are considered as light metals. Let us discuss it.

Aluminium is definitely lighter and weaker than steel. Steel is heavier and stronger because of the presence of the high concentration of carbon in it. Aluminium has 1/3 weight of steel.

Why and how aluminium is lighter than steel?

Aluminium is lighter than steel because it has much lesser density than steel. It possesses density 2.8 g/cm3 whereas steel has density almost 7.8 g/cm3. Due to lower density and atomic weight, aluminium acquires light weight with respect to steel.

Is aluminium malleable?

Malleability is a property of any material by which it can be beaten and form sheets from it. Let us talk about this in detail.

Aluminium is definitely a soft and malleable metal and they can be bent and given shape without breaking. A huge variety of product can be formed from aluminium due to its malleable nature. This malleability arises because of the formation of atomic layers which can slide over one another when the metal is getting stress.

Is aluminium radioactive?

Radioactivity arises due to having an unstable nucleus which can emit α, β and γ rays to stabilize itself. Let us explain it in detail.

The aluminium-26 isotope is radioactive with half life 7.17×105 years and proceeds through positron decay and electron capture to form magnesium-26 to get the stabilization. It also emits x-ray and gamma rays. But the aluminium-27 isotope is not a radioactive element as it has a stable nucleus.

Conclusion

Aluminium is a useful metal which shows high conductivity of heat and electricity. It is a soft malleable metal having density lower than most of the metals.