Anatomy of the Atom

Learning Goals  I will be able to identify parts of the atom.  I will be able to draw Bohr-Rutherford diagrams.

Subatomic Particles  In each atom, there are three subatomic particles: ParticleLocationChargeSize/MassSymbol Proton Inside the nucleus +1 1 a.m.u (atomic mass unit) p+p+ Electron Outside the nucleus 1/2000 a.m.ue–e– Neutron Inside the nucleus 01 a.m.un0n0

Anatomy of an Atom p+nop+no Shells Nucleus (proton and neutron) Electron

Atomic Number  Every element is identified on the periodic table by its atomic number.  The atomic number tells us the amount of protons an atom of that element has.  No two elements have the same atomic number.

Atomic Number  The atomic number also tells us the number of electrons present.  In all neutral atoms, the # of protons = the # of electrons.

Atomic Mass  The atomic mass of an atom represents the total sum of the protons and neutrons inside the nucleus.

Standard Atomic Notation  Identifies important information He 4 2 Atomic mass Atomic number

Aluminum  Write aluminum in standard notation.  How many protons?  How many electrons?  How many neutrons?

Finding Nemo … or Neutrons  To determine the number of neutrons in an element … math!  # neutrons = (atomic mass) – (atomic number)

Bohr- Rutherford Diagrams 1.Draw the nucleus as a solid circle. 2.Put the number of protons (atomic number) in the nucleus with the number of neutrons (atomic mass – atomic number) under it. 3.Place the number of electrons (same as protons) in orbits around the nucleus by drawing circles around the nucleus. Remember: 1 st shell – 2 electrons 2 nd shell – 8 electrons 3 rd shell – 8 electrons 4 th shell – 18 electrons.

Example  Phosphorous!

Learning Goals  I will be able to identify parts of the atom.  I will be able to draw Bohr-Rutherford diagrams.

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