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Atomic Theory - Coggle Diagram
Atomic Theory
Dalton's Theory
Matter is made of atoms
elemet made of one atom
mass is same for all elements of that atom
identical chemical properties
atoms of element differ from atoms of all other elements
compound - atoms of two or more elements combined
atoms neither created or destroyed during chemical change - atoms just rearranged to make different substances
Atomic Mass
single atom = to mass number
all isotopes present
typically not a whole number due to most elements being mixtures of two or more isotopes
average mass of all isotopes in sample of element
average mass = (fractional abundance x isotopic mass)
Measurements of atoms
Ions
same positively charged protons and negatively charged electrons = neutral
atomic charge = number of protons - number of electrons
protons and electrons are NOT equal = ion
atoms that gain one or more electron = anion
atoms that lose one or more electrons = cation
Dalton(Da)
fundamental unit of change(e)
Unified atomic mass unit (u)
atomic mass unit(amu)
"carbon 12"
Atomic Number
number of protons in the nucleus
same number of electrons
Mass Number
total number of protons and neutrons
number of neutrons is Mass - Atomic Number = number of neutrons
Chemical Symbols
Two letters <112
Three Letters > 112
First letter Capitalized
Symbol for specific Isotopes
Mass number as superscript to left
Atomic number sometimes listed but often omitted
All Mg atoms have 12 protons
Mg-24, Mg-25, Mg-26 all have 12 protons
Differ due to number of neutrons in nucleus
naturally occurring isotopes
Joseph Proust
Law of definite proportions
law of constant composition
law of multiple proportions
Isotopes
types of atoms with different masses that are cheically indistinguishable
= Atoms of the same element with different mass