Structure of the Atom or “Let’s Get up and Atom” Chemical Symbols Nucleus/ clouds Subatomic Particles Atomic Terms

Metal that forms bright blue solid compounds. Chemical Symbols Capitals matter! Element symbols contain ONE capital letter followed by lowercase letter(s) if necessary. Metal that forms bright blue solid compounds. Co vs. CO Poisonous gas.

Subatomic Particles in a neutral atom Most of the atom’s mass. NUCLEUS ELECTRONS in a neutral atom PROTONS NEUTRONS NEGATIVE CHARGE POSITIVE CHARGE NEUTRAL CHARGE Most of the atom’s mass. Atomic Number equals the # of...

Subatomic Particles Quarks 6 types He 3 quarks = 1 proton or 1 neutron

II. Electron Clouds (shells) Contain electrons (-) Orbital Energy Levels Bohr Model Diagrams

Orbital Region where there is 90% probability of finding an electron. Can’t pinpoint the location of an electron. Density of dots represents degree of probability.

Orbitals have different shapes.

Energy Levels Electrons can only exist at certain energy levels. Low energy levels are close to the nucleus. Each energy level (n) can hold 2n2 electrons.

Bohr Model Diagrams Simplified energy levels using Bohr’s idea of circular orbits. Can replace with: 3p 4n Lithium Atomic #: 3 Mass: 7 # of p: 3 # of e: 3 # of n: 4 e- e- p n Maximum e- Level 1 2e- Level 2 8e- Level 3 18e- Level 4 32e- e-

Bohr Model Activity Choose a number between 1 & 18. Find your element by the atomic number you picked. Draw a Bohr Model diagram for your element on your marker board. Round off the mass listed on the table and subtract the atomic # to find the # of neutrons. Abbreviate the # of ‘p’ and ‘n’ in the nucleus. Have a partner check your drawing. Repeat with a new element.

Atomic Number (Z) Mass Number (A) Atomic Mass unit (amu) Isotopes Atomic terms Atomic Number (Z) Mass Number (A) Atomic Mass unit (amu) Isotopes

Atomic Number (Z): Number of Protons In a neutral atom the # of protons = number of electrons P+ = e- 14+ = 14-

Mass Number Always a whole number. # of neutrons = A - Z Total # of nucleons (protons + neutrons) in nucleus of atom. # of P+ (+) # of n- © Addison-Wesley Publishing Company, Inc. Always a whole number. # of neutrons = A - Z # of neutrons = mass # - atomic #

Atomic Mass 1 proton = 1 u 1 neutron = 1 u 1 u = 1.67  10-24 g atomic mass unit (amu) = unit to describe the mass of an atom 1 u = 1/12 the mass of a 12C atom 1 proton = 1 u 1 neutron = 1 u 1 u = 1.67  10-24 g

Particle Symbol Charge Electron e" -1 Proton P+ +1 1 amu Neutron Mass in amu Mass in grams Electron e" -1 1/1 840 amu 9.11 x 10-28g Proton P+ +1 1 amu 1.67 x 10-24g Neutron N+- or n0 1.67 x 10 -24g © Addison-Wesley Publishing Company, Inc.

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