Atomic Structure Objective SWBAT describe the structure of

Atomic Structure Objective: SWBAT describe the structure of an atom. SWBAT use atomic # and mass to calculate the # of subatomic partices Bellringer: What is the charge of the following: Protons, Electrons, and neutrons?

ATOMIC STRUCTURE Particle Charge proton + charge neutron No charge electron - charge

HELIUM ATOM Shell proton + - N N + electron What do these particles consist of? - neutron

ATOMIC STRUCTURE Particle proton Charge + (positive) charge Mass 1 neutron No charge 1 electron - (Negative) charge nil

Atomic Mass Units • We use Atomic Mass Units (amu) to measure the mass of atomic particles. • 1 amu = 1. 660538921(73)× 10− 27 kg • 0. 0000000000000166053 8921 kg

Goal: Draw a Bohr Model of an Atom Steps: 1) Determine the number of protons, neutrons, and electrons. 2) Draw nucleus with protons and neutrons 3) Draw electrons in proper orbitals

Step 1: Determine the number of protons, neutrons, and electrons How do we know how many protons, neutrons, and electrons an atom of an element has?

ATOMIC STRUCTURE He 2 4 Atomic number the number of protons in an atom Atomic mass the number of protons and neutrons in an atom number of electrons = number of protons Atomic Mass – Atomic Number = # or Neutrons

ATOMIC STRUCTURE Guided Practice: H: Hydrogen 1 Atomic Number = _____ 1 # of protons = _____ 1 # of electrons = _____ Atomic Mass = _____1 # of neutrons = ____0

ATOMIC STRUCTURE Guided Practice: Helium 2 Atomic Number = _____ 2 # of protons = _____ 2 # of electrons = _____ Atomic Mass = _____4 # of neutrons = ____2

ATOMIC STRUCTURE Guided Practice: Lithium 3 Atomic Number = _____ 3 # of protons = _____ 3 # of electrons = _____ Atomic Mass = _____7 # of neutrons = ____4

Step 2: Draw nucleus with protons and neutrons He: Protons = 2 Neutrons = 2 += += Or P=2 N=2

Guided Practice H: Protons = 1 Neutrons = 0 + Or P=1 N=0

Guided Practice Li: Protons = 3 Neutrons = 4 + = = += Or P=3 N=4

Step 3: Draw the electons in the electron orbitals How do we know where to put the electrons?

Electrons are arranged in Energy Levels or Shells around the nucleus of an atom. • first shell a maximum of 2 electrons • second shell a maximum of 8 electrons • third shell a maximum of 8 electrons • fourth shell • fifth shell • sixth shell a maximum of 18 electrons a maximum of 32 electrons Fill up the lowest orbital before moving to next!!

Step 3: Draw electrons in electron in orbitals He: Electrons = 2 ++ == Or - P=2 N=2 -

Guided Practice H: Electrons = 1 - + - Or P=1 N=0

Guided Practice - Li: Electrons = 3 + = = += - - Or P=3 N=4 - -

Assigned Practice Due tomorrow!!