The electronegativity of aluminium is 1.61 (Pauling scale). Aluminium can relatively easily surrender its three outermost electrons in many chemical reactions (see below). Possible oxidation states are -2 -1 +1 +2 +3.Īn aluminium atom has 13 electrons, arranged in an electron configuration of 3s2 3p1, with three electrons beyond a stable noble gas configuration. In the periodic table, the elements are listed in order of increasing atomic number Z.Įlectron configuration of Aluminium is 3s2 3p1. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. The configuration of these electrons follows from the principles of quantum mechanics. Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom. Therefore, the number of electrons in neutral atom of Aluminium is 13. The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. After falling to Earth, atmospheric shielding protects the meteorite fragments from further 26Al production, and its decay can then be used to determine the meteorite’s terrestrial age. Meteorite fragments, after departure from their parent bodies, are exposed to intense cosmic-ray bombardment during their travel through space, causing substantial 26Al production. Cosmogenic aluminium-26 was first applied in studies of the Moon and meteorites. Nearly all aluminium on Earth is present as this isotope, which makes it a mononuclidic elementĪluminium-26 is composed of 13 protons, 13 neutrons, and 13 electrons. the only one that has existed on Earth in its current form since the formation of the planet. It is the only primordial aluminium isotope, i.e. Other than 26Al, all radioisotopes have half-lives under 7 minutes, most under a second.Īluminium-27 is composed of 13 protons, 14 neutrons, and 13 electrons. Only 27Al (stable isotope) and 26Al (radioactive isotope, t 1/2 = 7.2×10 5 y) occur naturally, however 27Al comprises nearly all natural aluminium. This is consistent with aluminium having an odd atomic number. Of aluminium isotopes, only 27Al is stable. Mass numbers of typical isotopes of Aluminium are 27. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.įor stable elements, there is usually a variety of stable isotopes. Neutron number plus atomic number equals atomic mass number: N+Z=A.

The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10 -19 coulombs. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. Aluminium is a chemical element with atomic number 13 which means there are 13 protons in its nucleus.

Aluminum atomic number