1. Sub-atomic Particles Isotopes and Ions Bohr Model
Unit 3: Biochemistry
Sub-atomic Particles
Isotopes and Ions
Bohr Model

2. WHAT IS IT?
__________ The smallest basic unit of matter or any physical substance. __________ One particular type of atom. Can not be broken down into simpler substances. __________ A substance made up of atoms of different elements bonded together in a certain ratio.

3. Let’s draw a simple atomic model. What parts must be included?

4. Sub-Atomic Particles Particle Name Location Charge Proton
Found inside the nucleus
Positively Charged (+)
Neutron
Neutrally Charged (0)
Electron
Found in electron cloud
Negatively Charged (-)

5. Calculating Sub-Atomic Particles
__________ = The number of protons found in the nucleus. __________ = The sum of the protons and neutrons found in the nucleus. ** In a neutral atom, the number of _______ and the number of _______ are always equal! **

6. PRACTICE!! Calculate the sub-atomic particles for the following examples.

7. Isotopes and Ions
__________ = Two or more forms of the same element that differ in the number of neutrons found in the nucleus, resulting in different atomic masses.
__________ = a charged element, either + or –
Cation – positively charged ion (loss of e-)
Anion – negatively charged ion (gain of e-)

8. PRACTICE!! Calculate the sub-atomic particles for the following examples.

9. Energy Levels
Electrons are located in the electron cloud around the nucleus. The cloud is organized into energy levels. Each level can only hold a certain amount of electrons. 1st Energy Level – holds up to 2 electrons 2nd Energy Level – holds up to 8 electrons 3rd Energy Level – holds up to 8 electrons

10. What are Valence Electrons?

12. Drawing Bohr Models Draw the nucleus.
Write the number of protons and neutrons in the nucleus.
Draw the first energy level.
Draw the electrons in the energy levels according to the “2-8-8” Rule.
Keep track of how many electrons you put in each level and how many electrons you have left.

13. PRACTICE!! Draw the Bohr models for the following elements.

14. HOMEWORK!
Complete the Bohr Model Practice sheet. Use your notes from today to help you answer questions regarding sub-atomic particles and the Bohr Model. Due tomorrow!