atoms Flashcards
Atom
the basic unit of matter.
Atomic number
the number of protons in the nucleus of an atom.
Electron
– a negatively charged particle that moves around the nucleus.
Electron dot diagram
a diagram that shows the element symbol surrounded by dots
representing valence electrons.
Element
a pure substance that cannot be broken down into simpler substances by
ordinary chemical means
Energy Level
– a particular region where electrons can orbit a nucleus.
Ion
an atom or molecule that has an electrical charge because it has gained or lost
electrons.
Isotope
one of several forms of the same element
Mass number
the number of protons plus neutrons in the nucleus of an atom.
Neutron
a particle with no charge located in the nucleus of an atom
Nucleus
the positively charged, dense center of an atom.
Periodic table
a chart that organizes the chemical elements based on their properties.
Proton
a positively charged particle located in the nucleus of an atom
Radioactive
capable of releasing radiation
Valence electrons
electrons found in the outermost energy level of an atom
