Bohr Diagram

Things you need to know before you can draw Bohr Structures:

Atoms contain protons, neutrons, and electrons.

Protons

• Positively charged
• Located in the Nucleus
• Contribute to Mass
• Contribute to Charge
• Tell you which element you have
• # CANNOT change
• Are = to the Atomic Number

Neutrons

• Neutrally charged
• Located in the Nucleus
• Contribute to mass
• # CAN change (isotopes)

Electrons

• Negatively charged
• Located in the orbitals
• No mass
• Contribute to charge
• # CAN change

***Assume, for now, that all atoms are neutral. This means that #protons = #electrons***

Bohr Structure

• Shows ALL electrons
• Maps electrons in their orbitals

Orbitals can hold electrons. (n = orbital #)

• Orbital #1 can hold 2 electrons.
• Orbital #2 can hold 8 electrons.
• Orbital #3 can hold 18 electrons.
• Orbital #4 can hold 32 electrons.

Steps:

1. Ask yourself "How many protons are there in this neutral atom?"
2. Based on Mass #, determine number of nuetrons.
3. Since it's a neutral atom: # p = # e
4. Draw orbitals (# orbitals = Period #)
5. Place electrons in orbitals

How to place electrons:

1. Orbital #1 - electrons pair together at the top of the circle
2. All other Orbitals - electrons are place one at a time starting at the top, moving clockwise
3. Once you have four electrons in an orbital the electrons start pairing up.
4. Once you reach the max number that an orbital can hold you move to the next orbital.

Isotopes and Ions

Notes for Page 23.

Atoms are identified by their # of protons.

• The # of protons DOES NOT change
• The # of neutrons CAN change
• The # of electrons CAN change

When the # of neutrons and electrons change the atomic structure/description also changes.

Isotopes

• Atoms of the SAME element with DIFFERENT atomic masses
• Occur when a change in neutrons occurs
• All elements have at least two naturally occurring elements

Two ways to write isotopes

1)

Ex.

2)

Ex.

Ions

• Atoms with a charge
• Occur when there is a change in # of electrons

Two types:

1) Cation - positively charged ion

2) Anion - negatively charged ion

Charge is written in the top right corner of the chemical symbol

Quizzes

Quiz #1 is a great quiz!

Quiz #2 is another great quiz!

Quiz #3 is a very basic matching quiz.

Quiz #4 is a really great quiz.

Worksheets

This is a great worksheet on the Subatomic Chart that includes Isotopes and Ions.

This is a great worksheet on atomic structure with isotopes and ions.