Using the Bohr Model to Build an Atom

Remember what the periodic table gives you… # of p+ Or # of e- Atomic Number 7 = N Chemical Symbol 14.007 Atomic Mass = (# of n0) + (# of p+)

Number of Neutrons? You’ll need to do a little calculation… Remember that: Atomic number = p+ Atomic mass = (p+) + (n0) So to calculate # of n0… [(p+) + (n0)] – (p+) = Atomic mass – Atomic Number = # of neutrons n0

Let’s Build an Atom… He = p+ = n0 = e- 2 4.0026 Step 1: Build the Nucleus – insert protons. Step 2: Build the Nucleus – insert neutrons. Step 3: Construct the first orbital and fill it with up to 2 electrons.

Let’s Build a Bigger Atom… 5 10.811 Step 1: Build the Nucleus – insert protons. Step 2: Build the Nucleus – insert neutrons. Step 3: Construct the first orbital and fill it with up to 2 electrons. Step 4: Construct the second orbital and fill it with up to 8 electrons.

How Can We Do This On Paper? 15 30.974 15p+ 2e- 8e- 5e- 16n0 Step 1: Build the Nucleus – insert protons. Step 2: Build the Nucleus – insert neutrons. Step 3: Construct the first orbital and fill it with up to 2 electrons. Step 4: Construct the second orbital and fill it with up to 8 electrons. Step 5: Construct the third orbital and fill it with up to 8 electrons.

One More Time!! Mg 12 24.305 12p+ 2e- 8e- 2e- 12n0 Step 1: Build the Nucleus – insert protons. Step 2: Build the Nucleus – insert neutrons. Step 3: Construct the first orbital and fill it with up to 2 electrons. Step 4: Construct the second orbital and fill it with up to 8 electrons. Step 5: Construct the third orbital and fill it with up to 8 electrons.