Atoms and Molecules

Atoms and Molecules

1. What is the simplest unit of an element and how do we represent its structure?

   • What is the smallest particle?
     • Atom
       • How is the structure of an atom represented?
       • Why is an atom electrically neutral?
         • An atom contains an EQUAL number of protons and electrons.
         • A proton carries a positive charge while an electron carries a negative charge.
         • The positive charge and negative charge cancel each other out.
         • Thus, an atom is electrically neutral. It has no net charge.
         • Why do neutrons not contribute to the overall charge of an atom?
           • They do not have charges.
   • How many atoms do elements in the Periodic Table have?
     • Each element in the Periodic Table consists of only one atom.
   • What makes up the mass of of an atom?
     • Proton and Neutron have the same relative mass. Electrons has neligible mass [do not add up to the mass of an atom].

2. How do we represent the Simplest Units of Elements and some Compounds?

   • What is a molecule?
     • A molecule is made up of two or more atoms that are chemically combined.

3. Periodic Table of Elements

   • We can use the Periodic Table of Elements to find out the number of protons in an atom.
     • Elements are arranged in the Periodic Table in increasing number of protons.
       • No 2 elements have the same number of protons in their atoms
         • Number of protons in atoms differentiates the elements [unique atomic structures]

4. The Molecule & Atomic Technologies

   • What is a chemical formula?
     • - represent molecules
       • - identifies each constituent symbol element of the molecule by its chemical symbol
         • The chemical formula tells us number of each atom of the element
   • Gold plated orchids, medical purposes, provide nuclear energy, radiation therapy to cure diseases, medical imaging, Magnetic Resonance Imaging [MRi], X-Ray
     • Issues: used in nuclear power plants/atomic bombs. Accidents may result in loss of lives and environment pollution.

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