Developing atomic theory

Atomic theory: The theory that all matter is made out of tiny invisible particles.

The different Scientists and their creations

John Dalton: Discovered and named atoms

J.J Thompson: Discovered that atoms have negative particles called electrons

Ernest Rutherford: The gold foil experiment, discovered protons

James Chadwick: Found the neutron

The Alchemists: explored nature and practiced many different cultures

Ions

Full or stable octet: An electron arrangement where the valence shell is filled with 8 valence electrons ( 2 for hydrogen and helium)

Octet rule: a generalization stating that when atoms combine they tend to achieve 8 valence electrons

Ion: a charged entity formed when an atom gains or loses one or more electrons

Positive ions are cations and Negative ions are anions

Isotopes and Isotopic abundance

Isotopes: a form of an element in which the atoms have the same number of protons as all the other forms of that element, but different numbers of neutrons

Isotopic abundance: the percentage of a given isotope in a sample of an element.

Mass spectrometer: a measuring instrument used to determine the mass and abundance of isotopes

Radiation and Radio topes :

Radioactive decay: the spontaneous disintegration of the unstable isotopes

Nuclear radiation: energy or very small particles emitted from the nucleus of a radioisotope

Alpha particle: a product of nuclear decay emitted by certain radioisotopes; a positively charged particle with the same structure as the nucleus of a helium atom

Beta particle: a product of nuclear decay emitted by certain radioisotopes; a negatively charged particle identical to an electron

Gamma ray: a form of high energy electromagnetic radiation emitted by certain radioisotopes

Radioisotope: an isotope that spontaneously decays to produce 2 or smaller nuclei and radiation.

Periodic Trends

Periodic law: a rule which states that when elements are arranged in order of increasing atomic number, their properties show a periodic recurrence and gradual change.

Atomic radius: distance from the nucleus of an atom to the outermost electron.

Ionic radius: Distance between the nucleus of an ION to the outermost electron.

Positive ions (cations): smaller atomic radius than their atom

Negative ions (anions): Larger atomic radius