Chemistry - The Structure of an Atom Vocabulary

Proton

Positively charged particle found in the nucleus

Neutron

no charged particle found in the nucleus

Electron

Negatively charged particle found in the nucleus

Nucleus

the center of the atom that contains all of the mass and all of the positive charge 

Isotope

atom with different numbers of neutrons and protons

Half-life

the amount of time it takes for one half of a sample to break down into products or decay by emitting radiation

Radiation

particles or energy emitted from the nucleus of an atom

Strong Force

very strong, short reach and attractive force

Electrostatic force

the attractive or repulsive force between charged objects

Alpha Particle

a particle made up of two neutrons and two protons

Beta Particle

consists of fast moving electron-like particles from the nucleus

Gamma Radiation

high energy radiation that passes no mass or charge

Fusion

the bonding of a small atom that starts at an high temperature

Fission

the splitting of a big atom that starts at normal temperatures with a bullet

Nuclear Equation

symbolic representation of a nuclear reaction, which involves the transformation of an atomic nucleus

Radioisotope

an unstable form of an element that releases radiation to become more stable

Nuclear atom

has a central, dense nucleus containing positive protons and neutral neutrons

Cation

a positively charged atom

Anion

a negatively charged atom

Ion

a atom that has a difference in charges

Electromagnetic Force

repulsive in the nucleus and has a long reach

Mass Number

not shown on the periodic table - the mass of an individual isotope of an atom (protons + neutrons = sum)

Atomic Number

shown on the table - the number of protons that identify the element

Atomic Mass

shown on the table - the weighted average of all naturally occurring isotopes that exist for an element 

What was the last subatomic particle to be discovered?

the neutron because it has no charge and is located at the center of the nucleus