Atomic Structure

The tiniest unit of matter can be divided without releasing electrically charged particles. It is also the smallest unit of matter that has the properties of a chemical element.

The majority of the atom is made up of empty space. The rest is made up of a cloud of negatively charged electrons surrounding a positively charged nucleus of protons and neutrons. In comparison to electrons, which are the lightest charged particles in nature, the nucleus is small and dense. Electric forces attract electrons to any positive charge; in an atom, electric forces bind electrons to the nucleus; because of the nature of quantum mechanics, no single image has been completely satisfactory for visualising the atom’s various characteristics, forcing physicists to explain different properties using complementary pictures of the atom. 

The electrons in an atom behave like particles orbiting the nucleus in some ways. In others, the electrons behave like waves around the nucleus that are frozen in place. Orbitals are wave patterns that describe the distribution of individual electrons. These orbital properties have a significant impact on an atom’s behaviour, and orbital groupings known as shells determine an atom’s chemical properties.

Explain the atomic model and the structure of an Atom

The mass of an atom can be used to identify it. When one of an atom’s electrons is removed, the atom’s trajectory bends when it passes through a magnetic field. The radius by which the magnetic field turns the trajectory of a moving ion is determined by the atom’s mass. This principle is used in mass spectrometers to determine the mass-to-charge ratio of ions. If a sample contains multiple isotopes, the mass spectrometer can determine the proportion of each isotope by measuring the intensity of different ion beams.

The atomic model is a model for describing the structure and composition of an atom that has evolved over time. The atom has been studied extensively as a component of the universe in order to understand better how atoms make up the universe.

Democritus, a Greek philosopher, is credited with coining the term “atom.” All matter, he said, is made up of indivisible particles called atoms that are surrounded by empty space.

The constitution of an element’s nucleus and the arrangement of electrons around it are referred to as its atomic structure. The nucleus of the atom is made up of protons and neutrons, which are surrounded by the atom’s electrons. The total number of protons in an element’s nucleus is described by its atomic number.

Protons and electrons are in equal numbers in neutral atoms. Atoms, on the other hand, can gain or lose electrons to increase their stability, and the resulting charged entity is known as an ion because different elements have different numbers of protons and electrons, and their atomic structures differ. This is why different elements have different characteristics.

The Atomic Theory of Dalton

John Dalton compiled experimental data collected by himself and other scientists in the early 1800s and discovered a pattern that is now known as the “law of multiple proportions.” He noticed that the content of a chemical element in chemical compounds containing that element varies by small whole-number ratios. Dalton deduced from this pattern that each chemical element combines with other elements through some basic and consistent unit of mass.

For example, Dalton looked at two types of iron oxides: a black powder with 78.1 percent iron and 21.9 percent oxygen and a red powder with 70.4 percent iron and 29.6 percent oxygen. Using these figures, there is approximately 28 g of oxygen in every 100 g of black oxide; for every 100 g of iron, there is about 42 g of oxygen in red oxide. The ratio of 28 to 42 is 2:3. There are two or three atoms of oxygen for every two atoms of iron in these oxides (Fe2O2 and Fe2O3).

Atomic Model of Thomson

The Nobel Prize was later awarded to Sir Joseph John Thomson for the discovery of “electrons.” His research is based on a procedure known as the cathode ray experiment.

Experiment with Cathode Rays

It features a glass tube with two openings: one for the vacuum pump and the other for the gas inlet.

The vacuum pump’s job is to keep the glass chamber at a “partial vacuum.” Inside the glass tube, electrodes (cathode and anode) are connected to a high voltage power supply.

Atomic Theory of Rutherford

With the discovery of another subatomic particle called “Nucleus,” Rutherford, a student of J. J. Thomson changed the atomic structure. The Alpha ray scattering experiment inspired his atomic model.

Experiment with Alpha Ray ScatteringThe majority of the rays passed through the gold foil, resulting in scintillations (bright spots) on the ZnS screen.

After hitting the gold foil, one out of every 1000 rays was reflected at an angle of 180° (retraced path).

Rutherford concluded that the majority of the space inside the atom is empty because most rays passed through.

Conclusion

Thomson described the atomic structure as a positively charged sphere with negatively charged electrons embedded in it, based on the results of his cathode ray experiment. According to Thomson’s atomic structure, atoms are electrically neutral, meaning that the positive and negative charges are of equal magnitude.