• Matter- the stuff that makes up everything in the universe
• Element- A substance that cannot be broken down into other
substances by chemical or physical means
• Compound- A substance made of two or more
elements
chemically combined
• Mixture- Two or more substances that are mixed
together but
not chemically combined
• Atom- The smallest particle of an element
• Molecule- A combination of two or more atoms that are
bonded together
• ATOMS = BUILDING BLOCKS
• Atoms are the basis of chemistry. They
are the basis for everything in the
Universe.
• There are three basic parts of an atom.
The parts are the electrons, protons, and
neutrons.
• The protons and neutrons are always in
the center of the atom.
• Scientists call the center of the atom the
nucleus.
• The electrons are always found whizzing
around the center in areas called orbitals.
Draw in your notebook
Draw in your notebook
This is a Bohr Model of an
atom.
• The atom is made up of three parts:
• Proton(+)-Small, positively charged particles in the
nucleus of an atom
• Neutron(0)-Small uncharged particle in the nucleus
of an atom
• Electron(-)-a tiny, negatively charged, high-energy
particle that moves in the space outside the nucleus
of an atom
Atomic Number
• The number of protons in the nucleus of
an atom
• The identity of an atom is determined by
the Atomic #
• Helium has 2 Protons, its atomic number
is 2
Atomic
Number
The Periodic Table
Atomic weight
How to find the # of Protons,
Neutrons, & Electron
• Protons-Same amount as the atomic #
• Electrons- Same as the # of protons
• Neutrons- The atomic mass – the atomic #
Sodium
11
Protons: 11
Neutrons: 12
Electrons: 11
Na
23
Atomic Mass
• The average mass of one atom of an
element
Valence Electrons
• The number of electrons in the outermost
orbit of an atom
Isotope
• An atom with the same number of protons
and different number of neutrons (and
therefore different atomic masses)
• Example: Carbon -12
Carbon -14
Examples of Carbon Isotopes
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