This document provides a review of key concepts in atomic structure: 1) Protons have a positive charge and determine the atomic number, neutrons have no charge and determine isotope variations, electrons have a negative charge and determine ion charge state. 2) Atomic mass is the total number of protons and neutrons, while the atomic number indicates just the number of protons. Neutrons can be calculated by subtracting the atomic number from atomic mass. 3) Elements are arranged on the periodic table by atomic number, which identifies each unique atom, while isotopes of an element can vary in neutron number.

1. Atomic Structure Review

2. Protons Positive Charge 1 atomic mass unit Located in nucleus The number never changes

3. Neutrons No charge 1 atomic mass unit Located in the nucleus The number changes based on atomic mass. A new # of neutrons=isotope.

4. Electrons Have a negative charge No mass Located outside of the nucleus Atoms can gain or lose electrons. Gain electrons, negative charge. Lose electrons, positive charge.

5. Determining Atomic Mass Atomic mass is the number of protons and neutrons together. Electrons do not count, they have no mass. To find the number of neutrons, subtract the atomic number from the atomic mass.

6. Atomic Number Elements are arranged on the periodic table based upon their atomic number. Atomic number tells us the number of protons in an atom. The identity of the atom is based on the protons!!!!

7. Isotopes Know how to find an isotope. Be able to calculate the number of neutrons and protons. Understand that one atom can have several different isotopes.

8. Ions Atoms carrying a charge. New net charge, either positive or negative. Electrons gained=negative Electrons lost=positive

9. Electron Levels S level, fills with 2 electrons P level, fills with 6 electrons D level, fills with 10 electrons

10. Be able to identify an atom based on the electron configuration. If given an element, be able to give its configuration.