Subatomic Particles In the Nucleus: In the Electron Cloud: Protons: + charge Neutrons: no charge Mass of each:1 atomic mass unit (amu) Electrons: - charge Practically no mass
Check What are the two overall structures in the atom? What are the names of the atomic particles?
What’s an element? Atoms with different numbers of protons
Atomic Number # of protons=atomic number Identification (student id# or SSN)
Why is it called “periodic”?
Check Where are the protons located? Where are the electrons located? Where are the neutrons located?
Mass Number Protons + Neutrons
Exercise Draw a neutral lithium atom (protons, neutrons, electrons) with an mass number of 7
Isotope Atom with same # of protons but different # of neutrons (different mass number)
Radioactivity Too many or too few neutrons compared to protons UNSTABLE It wants to be sane (more stable)…so it gets rid of something! Emits a particle or energy Ever heard of uranium? Types of nucleus radiation that can be emitted: Alpha Beta Gamma
Check What is the atomic number?
Atomic mass Weighted atomic mass of the isotope of an element
Structure of an atom Electron Cloud Nucleus
Electron cloud Electrons arranged in Energy level 1st level can hold 2 electrons 2nd energy level can hold 8 3rd…18 4th…32 Outermost electrons called valence electrons – chemical bonds
Exercise Draw a neutral carbon atom with an atomic mass of 12 Draw the electron cloud of Na Draw the electron cloud of Cl
Bonding As it turns out, atoms bond together for a very simple reason: atoms like to have full valence shells http://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm http://www.kentchemistry.com/links/bonding/bondingflashes/bond_types.swf
Ions Atoms that are Not neutral # Electrons not equal to # protons Previous example of sodium and chlorine
Part K on review sheet
States/Changes of matter Solids, liquids, gases http://www.chem.purdue.edu/gchelp/liquids/character.html http://www.clickandlearn.org/Gr9_Sci/Particle_Theory.htm