Researchers Describe Oxygen’s Different Shapes

Oxygen-16, one of the key elements of life on earth, is produced by a series of reactions inside of red giant stars. 

Now a team of physicists, including one from North Carolina State University, has revealed how the element’s nuclear shape changes depending on its state, even though other attributes such as spin and parity don’t appear to differ. 

Their findings may shed light on how oxygen is produced.

Carbon and oxygen are formed when helium burns inside of red giant stars. 

Carbon-12 forms when three helium-4 nuclei combine in a very specific way (called the triple alpha process), and oxygen-16 is the combination of a carbon-12 and another helium-4 nucleus.

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The shape of oxygen-16 in its ground and first excited state. Credit: Dean Lee et al.

 

Rutherford Gold Foil Experiment

Atomic Line Spectrum

 
Credit: http://www.mhhe.com/physsci/chemistry/essentialchemistry

Millikan Oil drop Experiment

 

Credit: http://www.mhhe.com/physsci/chemistry/essentialchemistry

Atomic Chemistry

Atom, smallest unit of a chemical element that can exist. In ancient Greek philosophy the word “atom” was used to describe the smallest bit of matter that could be conceived of. This “fundamental particle”, to use the present-day term for this concept, was thought of as indestructible; in fact, the Greek word for atom (atomos) means “not divisible”. 

Knowledge about the size and nature of the atom did not begin to be acquired until long after the beginnings of experimental science in the 16th and 17th centuries. Although many of the new “experimental philosophers” believed in the reality of atoms, the progress of science owed little to the idea. The first quantitative explanation of the behaviour of matter in terms of atoms was attempted by Daniel Bernoulli in 1738, but his work was largely ignored. However, chemistry was discovering things about matter that only the idea of atoms could explain. 

Chemists recognized that all liquids, gases, and solids can be broken down into their ultimate components, or elements. For example, salt is a chemical compound formed when the elements sodium and chlorine react together and become joined in an intimate form known as a chemical compound. Air, by contrast, was found to consist of a mixture of the gases nitrogen and oxygen, which do not react with each other.

Credit: library.thinkquest.org/

A SIMPLE VIEW OF ATOMIC STRUCTURE

What happens if a beam of each of these particles is passed between two electrically charged plates - one positive and one negative? For more details click here.

Courtesy: Jim Clark, http://www.chemguide.co.uk

Isotope, Isobar and Isotone

1. Isotope: Atoms or ions of an element with different numbers of neutrons in their atomic nucleus. Isotopes have the same atomic number but different mass number. Isotopes have very similar chemical properties but sometimes differ greatly in nuclear stability.



Image Courtesy of  http://www.suntrek.org

2. Isobar: Nuclides that have the same isotopic mass but different atomic number. 

3. Isotone: A group of atoms or ions with nuclei that contain the same number of neutrons but different numbers of protons. 



Image Courtesy of http://www.notespal.com

Atomic Spectra

Bohr model has its ability to predict the spectra of light emitted by atoms. In particular, its ability to explain the spectral lines of atoms as the absorption and emission of photons by the electrons in quantized orbits.

 Courtesy: http://abyss.uoregon.edu

Evolution of Atomic Theory

Courtesy: http://www.scienceclarified.com

Orbital Box Diagram

Electron filling in atomic orbitals following Aufbau principle [or building-up principle], Pauli exclusion principle [or Antisymmetry principle] and Hund's rule of maximum multiplicity.

Courtesy: Richard C. Banks, Professor of Chemistry, Boise State University.

Electronic configuration from Hydrogen to Calcium

Courtesy: Dr. Mike Thompson

Origin of Lyman and Balmer series in the Hydrogen spectrum

Courtesy: Chris Evans and Dr. Mike Thompson

Aufbau principle

Courtesy: Dr. Mike Thompson

Photon Absorption and Emission by Electron

electron transition

Courtesy: Dr. Mike Thompson

Electron shells related to Periodic Table

no. of shells across a period and within a group

Courtesy: Dr. Mike Thompson

Electronic structure of an atom

Electronic structure showing shells

Maximum no. of electrons in each shell

Courtesy: Dr. Mike Thompson