Nuclear Decay

What is Nuclear Decay?


Nuclear decay, also known as radioactive decay, describes the process wherein an atom is transmutated into a different element. There are five different types of nuclear decay, and they are detailed in this section.

Alpha Particle


Circled in the image above is the alpha particle. The equation above details the change that takes place during alpha decay. It is important to memorize the alpha particle, as well as the other particles detailed on this page.

Neutron Particle


This equation above takes fluorine and outputs an isotope of that same element. This is due to the neutron particle that is circled above.

Positron Particle


Above is an example of positron emission. The transition from boron to carbon occurs due to the positron particle, which is circled above.

Beta/Electron Particle


In the picture above, a reaction is shown. What is circled is the beta particle, which is the key piece of the equation. The beta particle is also known as the electron particle. 

Half life

Half life is a very important idea in chemistry. This formula considers the time it takes for a substance's quantity to be halved. It is important that all students memorize the formula to the right. Under the large umbrella of half life problems, there are a few different ways that these problems can be asked. 

1. One way is that the final amount of substance, the initial amount of substance, and the time can be given. Using the properties of logs, the half life (k) can be calculated. 



Atomic Models



In Progress

John Dalton

In Progress

JJ Thomson

In Progress

Ernest Rutherford

In Progress

Niels Bohr

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Erwin Schrodinger

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Intermolecular Forces


Intermolecular forces are the interactions between molecules. Governed by the relationships between electronegativity, polarity, and molecular geometry, intermolecular forces result in many physical properties of compounds. These include: 

  • Melting point
  • Freezing point
  • Boiling point
  • Evaporation
    • Alcohol is faster than water
  • Surface tension
  • Form of matter: solid, liquid, gas
    • solidification/condensation
  • Viscosity (ability to flow)

Relative Strength of Attractive Forces

The following forces are listed in order of strongest to weakest attraction between the molecules: 

Network Covalent> hydrogen bonding > dipole dipole > dispersion

Network Covalent

Network covalent structures are a very strong intermolecular force. In these structures, attractive forces cause the molecules line up in a tight grid structure. This is seen in silicon or carbon structures because they are tetravalent (form 4 bonds). Examples include diamond (C), graphite (C), and SiO2.

Hydrogen Bonding

As a wise chemist once said, “Water is number one in hydrogen bonding.” Because of its low electronegativity, Hydrogen atoms assume a slightly positive charge in compounds that contain Fluorine, Oxygen, and Nitrogen. This slightly positive charge is attracted to the slightly positive charge on the Fluorine, Oxygen, or Nitrogen of another molecule. Remember, Hydrogen just wants to have FON.

Water is the perfect example of hydrogen bonding because the H atoms are attracted to the O atoms of another molecule. This results in water's high boiling point.


Dipole-Dipole interactions are caused by differences in polarity between different points on a molecules, or the net dipole of the molecule. Similar to hydrogen bonding, slightly positive atoms on one molecule are attracted to slightly negative atoms on another, resulting in an attractive force between molecules.

Visit the bonding page to learn more about identifying polar and non-polar structures. 

London Dispersion Force

London Dispersion forces occur between every molecule. Under the category of van Der Waals forces, London Dispersion forces push the electrons of atoms apart. The more valence electrons an atom has, the stronger the repulsive force will be.