The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
The atomic composition leads to the atomic structure having a nucleus that is in the centre. In the nucleus, there are protons that are positively charged and neutrons that have no charge i.e they are neutral). In the heart of the nucleus, the negatively charged particles called electrons revolve.
An element’s atomic structure consists of the nucleus and the configuration surrounding the e–. Primarily, protons, neutrons and electrons form the atomic structure of matter.
The atom’s nucleus, which is encircled by the electrons owned by the atom, is made up of protons and neutrons. An element’s atomic number represents the sum of protons in the nucleus. Neutral atoms consist of protons, electrons in equal quantities. However, to improve their steadiness, atoms may obtain or drop electrons and the charged entity is referred to as an ion. As they hold different numbers of electrons & protons, atoms of various elements have various atomic structures. This can be said as the explanation for the distinctive features of multiple parts.
With the assistance of atomic structures, many physicists sought to clarify the composition of the atom in the 18th and 19th centuries. Both of the models had eminence and demerits of their own and were central to the modern atomic model’s development. The scientists’ John Dalton, Sir Joseph John Thomson, Ernest Rutherford, and Niels Bohr’s atomic model made the most notable contributions to the field.
Thomson’s Atom Structure
In the early 1900s, Sir JJ Thomson presented his model that represented the structure of the atom.
Bohr’s Atomic Model
The Bohr atom model was introduced by Neil Bohr in 1915. It came into being with the update of Rutherford’s atom model. Rutherford’s model introduced the nuclear model of an atom, stating that the nucleus (positively charged) is surrounded by negatively charged electrons.
Bohr changed this atomic structure model by demonstrating that electrons pass in fixed orbitals (shells) and not somewhere in between, and also demonstrated that each orbit (shell) has a fixed energy level. Rutherford ultimately clarified the nucleus of the atom, and Bohr changed the model into electrons and their energy ranges.
Valency is a measure of the potential of atoms or molecules to bind.
The atomic number of the chemical element is the number of protons present in the nucleus of each atom of that element.
The mass number is the cumulative number of protons and neutrons (known collectively as nucleons) in the atomic nucleus.
Experiment on Cathode Ray
The cathode ray experiment consists of a glass tube with two holes, one hole is for the vacuum pump and the other hole is for the inlet from which the pumping of the gas takes place. The vacuum pump is responsible for maintaining the “partial vacuum” inside the glass chamber. Using electrodes, i.e. cathode, a high voltage power supply is attached and the anode is fitted within the glass tube.
Thomson’s atomic model fails to precisely explain the stability of an atom. It was therefore not necessary to put further observations of other particles (subatomic in nature) inside his atomic model.
Rutherford’s Atomic Model
Rutherford Atomic Model Drawbacks
Isotopes’ Atomic Structure
The elements of an atom’s nucleus are nucleons. A nucleon is either a neutron or a proton. There is a distinctive number of protons in each element that is expressed by its distinctive atomic number. There may, however, be multiple atomic structures of an element, which vary in the total sum of nucleons.
Such variation of elements with a particular number of nucleons (known as the number of masses) is referred to as element isotopes. Hence, the isotopes of an element have an equal number of protons but vary in the number of neutrons.
This chapter taught us about the structure of atoms. We learned about the different models, atomic number, and mass number of the atoms. We also learned about the valency of the atoms.
Protons, electrons, and neutrons are components of an atom. A proton is charged positively and is found in the atom’s centre or nucleus.
Although the concept of the atom dates back to Democritus’ ideas, the first modern description of it as the fundamental building block of chemical structures was formulated by the English meteorologist and chemist John Dalton.
In the solar system, the four most abundant atoms are hydrogen, oxygen, carbon, and nitrogen.
On a single proton, the amount of charge is equal to the amount of charge that a single electron possesses. A proton and an electron have an equal quantity but an opposite charge type. The atom is thus defined as being electrically neutral if an atom comprises equal numbers of protons and electrons.
Atoms, the smallest unit into which, without the release of electrically charged ions, the matter can be separated. It is also the smallest unit of matter with the distinctive characteristics of a chemical element.
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