2.2 Flashcards
All matter is composed of …. Unique substances that cannot be broken down into simpler substances by ordinary chemical methods
Elements
An oddly shaped checkerboard provided a a listing of known elements and helps explain the properties of each element
Periodic table
Each element is composed of more or less identical particles
Atoms
We designate each element by one or two letter chemical shorthand
Atomic symbol
Bear a positive electrical charge
Protons (p+)
An atom has a central … containing protons and neutrons tightly bound together
Nucleus
Are neutral (n0)
Neutrons
1 AMU
Atomic mass unit
… bear a negative charge equal in strength to the positive charge of a proton
Electron (e-)
Simplified model of atomic structure
Planetary model
Regions around the nucleus in which a given electron or electron pair is likely to be found most of the time
Orbitals
Depicts regions of the greatest electron density by denser shading. A more modern model that uses orbitals to determine an area where an electron is most likely to be found.
Orbital model
Equal to the number of protons in its nucleus and is written as a subscript to the left of its atomic symbol (1H)
Atomic number
Sum of the masses if it’s protons and neutrons. Usually indicated by a superscript to the left of the atomic symbol
Mass number
Known element having two or more structural variations. Which have same number or protons and electrons but different number of neutrons.
Isotopes
