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Concept of the Atom - Coggle Diagram
Concept of the Atom
Atomic Theories
Dalton's Theory
- Atoms are in everything
- Atoms of the same element are identical
- Atoms can combine with other atoms in simple ratios.
- Chemical reactions rearrange the atoms but don't change their identity.
Democritus's Theory
- Atoms are the building blocks of life.
- Atoms are "indivisible".
- Nothing to support the theory.
Atomic Models
- Late 1700s
- Element: a substance that cannot be broken down.
- elements combine to create compounds
- by 1970s greater emphasis on quantitative analysis on chemical reactions
Plum Pudding Model
- Blueberries represented electrons in the muffin.
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The Atom
- Smallest partial of an element that retains the properties of the element.
- Can be seen with a scanning tunnel microscope.
Isotopes
- An unstable atom or a "radioactive".
- Same atomic number with different neutrons.
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The Nucleus
- Is the center of the atom.
- Makes up a majority of the atomic mass.
- Contains protons and neutrons.
Discovery of the Nucleus
- Ernest Rutherford found a massive area in the center of an atom.
- Stated that an atom is a tiny, dense, central cor of the atom.
Composed of protons and neutrons.
Subatomic Particles
Electrons
- Negatively charged particle.
- 0.1840x the size of a proton.
Outside of nucleus in the electron cloud.
Nuetrons
- A neutral charge
- Roughly the same size as proton.
- Inside nucleus.
Protons
- Positive charged particle.
- Roughly same size as neutron.
- Inside nucleus
Properties of the atom
Atomic Number
- Is the number of protons.
- Always the # that does not have a decimal.
- Periodic table is built on this number.
Mass Number
- The sum of protons and neutrons.
- Number of neutrons = mass # - atomic #.
- NOT on the periodic table
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Atomic Mass
- Atomic mass unit (AMU) = 1/12 of a carbon-12 atom.
- The weighted average of all the isotopes of an element.