![]() ![]() Electrons: The only type of atomic particles present outside the nucleus in the atomic space.Neutrons: These are also located inside the nucleus but are charge-neutral species.Protons: These are located inside the nucleus and confer a positive charge to it.The other atomic particles present in the nucleus are neutrons. It exhibits a positive charge owing to its constituent particles i.e. Nucleus: It is the heart or core of the atom.The pictorial representation also illustrates the mass number and the atomic number of the atom.īefore we move forward with the Bohr model of Lithium, I would like to describe a few terms that would help you have a better insight into the structure. The Bohr model describes the structure of the atom defining the place and charge of all the atomic species. the Bohr-Rutherford model explained that the electrons are the moving particles that revolve around the nucleus in a definite circular orbit that has fixed energy and size. The earlier model could not provide the reason for the stability of electrons revolving around the nucleus and hence, could not keep up with the laws of classical mechanics and electromagnetic theory. This model was actually the upgraded version of the earlier model proposed by Ernst Rutherford in 1911. Therefore, there are various non-equivalent definitions of atomic radius.The Bohr model of the atoms or more precisely, the Bohr-Rutherford model was proposed by Ernst Rutherford and Niel Bohr in 1913. However, this assumes the atom to exhibit a spherical shape, which is only obeyed for atoms in vacuum or free space. The atomic radius of a chemical element is a measure of the distance out to which the electron cloud extends from the nucleus. It must be noted, atoms lack a well-defined outer boundary. The atomic radius of Lithium atom is 128pm (covalent radius). Note that, each element may contain more isotopes, therefore this resulting atomic mass is calculated from naturally-occuring isotopes and their abundance. The atomic mass is carried by the atomic nucleus, which occupies only about 10 -12 of the total volume of the atom or less, but it contains all the positive charge and at least 99.95% of the total mass of the atom. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element. Mass numbers of typical isotopes of Lithium are 6 7. 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. Lithium is a chemical element with atomic number 3 which means there are 3 protons in its nucleus. Atomic Number – Protons, Electrons and Neutrons in Lithium ![]()
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