Atomic structure refers to the structure of an atom which consists of a positively charged nucleus present at the center and negatively charged particles Electrons revolve around it. The atom is the basic identical unit of any substance and its structure varies. The atomic structure of elements can be identified by deep study and research. The first Atomic Theory was introduced by John Dalton in 1800. Refer to this article to get all the details on Atomic Structure. The general atomic structure of an element is given below for a better understanding of students.
Atomic Structure in Chemistry
Atomic structure in chemistry refers to the establishment of the nucleus and the arrangement of the electrons around the nucleus of an atom. Mainly, the atomic structure of a substance is made up of protons, electrons, and neutrons. These are the basic entities of the atom. The protons are positively charged elements, electrons are negatively charged and neutrons are neutral. The atomic structure in chemistry can be determined for all 118 elements.
Atomic Structure Notes
The structure of an atom consists of a nucleus and the electrons revolve around it forming the atomic structure. Atomic structure notes are given in this article which is helpful for the aspirants to prepare well for the upcoming exams. The students can prepare atomic structure notes to enhance their preparation. You can follow this article for atomic structure notes in detail.
Atomic Structure Model
The word Atom is driven by the Greek word ‘Atomos’ which means ‘indivisible’. Atoms are made of electrons, Protons, and Neutrons. Protons and Neutrons are present in the nucleus of the atom and electrons orbit the nucleus all around. Atoms always have an equal number of protons and electrons and the number of neutrons and protons is usually similar as well. Protons and Neutrons are held together in the nucleus by a strong attraction force called the Nuclear force.
In the 18th and 19th centuries, many scientists and researchers sought to illustrate the structure of the atom with the help of atomic structure models. Each of these models had its own merits and demerits and was key to the development of the modern atomic model. The most significant contributions to this domain were by the scientists such as John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr. Their ideas and observations on the structure of the atom are discussed here in detail.
1. Ancient Greeks Belief in Atomic Structure
“All matter is made up of atoms, which are small units of matter.” All entity is made up of smaller units called atoms, as hypothesized by Leucippus and Democritus in the fifth century B.C. They also assert that these were solid elements with no internal structure that came in a variety of shapes and sizes. In addition, they developed immaterial traits such as taste and color.
2. Dalton’s Atomic theory
In 1808, Scientist John Dalton based his work on the Greek concept of atoms. He proposed that substance is made up of atoms, which he defined as tiny, indivisible units. He also asserted that, while all atoms of one element are identical, those of other elements are unique.
3. Sir J.J. Thomson’s Theory
In 1904, English scientist J.J. Thomson proposed the plum pudding” idea of the divisible atom. In addition, his model recommended that atoms are made up of a large positively charged sphere studded with negatively charged electrons (termed dubbed “corpuscles”), similar to the fruit in a plum pudding.
He also asserted that the charge of the positive sphere is equivalent to the charge on the electrons (negative charge). The positively charged particles are referred to as protons, while negatively charged particles are termed electrons.
4. Rutherford’s Theory
In 1911, British physicist Ernest Rutherford proposed a nuclear assumption for atoms. A nucleus is a component of an atom. He already identified the central part of the atom nucleus, where the movement of protons and electrons takes place. He also formulated that the number of protons and electrons in an atom is equal in number.
5. Bohr’s Atomic Theory
Niels Bohr, a Danish physicist, illustrated a planetary model in 1913, in which electrons rotate around the nucleus in the same way that planets orbit around the sun. The electrons have “constant energy” when they are in a shell. This assumption refers to these atoms as “stimulated” electrons when they grab the energy and go into a higher energy orbit. They leave this energy as electromagnetic radiation when they return to their primary orbit.
The electrons inside the atoms are put in discrete orbits called “stationery orbits,” according to the following postulates listed below:
- The energy level can be represented by the Quantum numbers.
- Electrons absorb the energy to move to higher energy levels and release their energy to go to lower energy levels or orbit.
- There will be no energy absorption or emission as long as an electron remains immovable.
- Only in these stationary orbits do electrons whirl around the nucleus.
- The static orbits’ energy is quantized.
Bohr’s Atomic Theory’s Limitations:
- Only single electron species such as H, He+, Li2+, Be3+, etc. deal with Bohr’s atomic structure.
- Each line range was seen to be a composite of several smaller distinct lines when the emission spectra of hydrogen were investigated using a more accurate spectrometer.
- Bohr’s theory went wrong to explain both the Stark and Zeeman effects.
6. Quantum Mechanics and Einstein, Heisenberg Theory
- As per the previous beliefs, the atom consists of a central and large nucleus enclosed by several electrons. Previously, electrons and other small particles were thought to be fixed solid “lumps.”
- Modern quantum theory, on the other hand, refers to them as statistical “clouds.” Furthermore, one can exactly measure their speed as well as their location. We can’t, still, accomplish both simultaneously.
- According to the Heisenberg principle, no two conjugate physical values can be measured with full accuracy at the same time. There will always be some error or uncertainty.
The drawback of Bohr’s Atomic Theory
Bohr accurately measured two conjugate quantities such as the position and momentum of electrons simultaneously (theoretically).
- The Stark effect is a phenomenon that arises when electrons are deflected in the existence of an electric field.
- The Zeeman effect is a phenomenon that emerges when electrons are deflected by a magnetic field.
Representation of Atom
The representation of the atom is done as given here.
As we know there are total of 118 elements discovered now. Here we are going to discuss the atomic structure of some important elements including Hydrogen, Carbon, Oxygen, Fluorine and Aluminum. So refer below to know the atomic structure of these elements.
Atomic Structure of Hydrogen
The hydrogen atom is the simplest of all the atoms. It consists of a single proton and a single electron. In addition to the most common form of the hydrogen atom is called protium, two other isotopes of hydrogen atom namely deuterium and tritium. The atomic structure of the hydrogen atom is given here.
Atomic Structure of Carbon
The carbon atom has an atomic number of 6. That means a carbon atom has 6 protons, 6 neutrons, and 6 electrons. Since carbon is in the second row (or second period), it has 2 electron orbits. The atomic structure he f carbon atom is given here.
Atomic Structure of Oxygen
The atomic number of Oxygen is 8. The nucleus of an oxygen atom consists of 8 protons and 8 neutrons. It features eight electrons placed on the electron orbits.
Atomic Structure of Fluorine
The atomic number of Fluorine is 9. The nucleus consists of 9 protons and 10 neutrons. Nine electrons occupy the available electron shells. Fluorine is a halogen element in group 17, period 2, and belongs to the p-block of the periodic table. The atomic structure of Fluorine atom is given here.
Atomic Structure of Aluminum
The atomic number of the Aluminum atom is 13. Its’s nucleus consists of 13 protons and 14 neutrons while 13 electrons unite to the nucleus, sequentially acquiring available electron orbits. The atomic structure of an Aluminum atom is given here.
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