1. Let’s Talk Chemistry!
The atom

2. 1. The Atom made up of protons, neutrons and electrons
basic unit of matter, VERY small
made up of protons, neutrons and electrons
the atom is neutrally charged (no charge)
The units used to measure the mass of the particles in an atom are the Atomic Mass Unit (amu)
Simplest and most basic unit of matter
Neutrally charged since they have the same number of protons and electrons
Atomic number of two:
Has two protons
Must have two electrons because the charge is neutral
Neutrons have no charge

3. Model of a Helium Atom: Atomic Number 2
proton
neutron
electron

4. 2. Structure of an atom
The nucleus of an atom:
Protons are positively charged
Mass is 1 amu
Neutrons have no charge
Electrons:
in constant motion around nucleus found in the electron cloud
negatively charged
Mass is 1/1840 amu
Atoms have an equal number of protons and electrons.

5. 3. Elements 110 known elements
Each element has its own unique number of protons
The number of protons is known as the atomic number
And… since the number of protons equals the number of electrons, you can use the atomic number to find the number of electrons as well!

6. But what about neutrons?
Each element also has a certain number of neutrons
To find the number of neutrons, you subtract the atomic number from the rounded atomic mass

7. Formulas! Atomic number = number of protons = number of electrons
Number of neutrons = rounded atomic mass – atomic number
More formulas! They are so helpful, I just want to remember them all!!

8. 5. Isotopes
Atoms that have the same number of protons but a different number of neutrons
The mass number is the sum of the protons and neutrons in an isotope

9. Carbon isotope challenge
For each example:
How many protons, neutrons, electrons?
Which ones are the isotopes?

10. Carbon isotope challenge
isotopes

11. 3. Elements on the periodic table
Pure substance
Made of one type of atom
Represented by 1, 2 or 3 letters
Number of protons in an atom is the atomic number (i.e. Carbon is 6, Oxygen is 8)
Since number of protons equals the number of electrons, Carbon has 6 electrons, Oxygen has 8 electrons

12. 4. History of the Periodic Table
Mendeleev designed the first periodic table
He arranged the elements by increasing atomic mass
He left blank spaces according to similarities in columns of elements

13. More history…
Mendeleev’s blank spaces (or predictions) were elements that he claimed were not discovered yet.
As it turns out, he was right!!
Scientists later discovered the missing elements with the properties that Mendeleev predicted!

14. And even more history! Moseley discovered the atomic number
He organized the periodic table by increasing atomic number
This allowed for elements with similar properties to fall into place
An gave way to the modern periodic table

15. 5. Molecules Smallest unit (part) of a compound Hydrogen molecule
Explain organic molecule and inorganic molecule:
Organic:
Must contain Carbon and Hydrogen
Inorganic:
Does not contain Carbon and Hydrogen
Some molecular compounds just contain Carbon, not considered to be organic
Carbon dioxide is an example of an inorganic molecule containing carbon
Diatomic molecule = two atoms joined together
A compound can also be a molecule, but a molecule cannot be a compound

16. 6. Compounds
a substance that contains two or more different elements
organic compounds must contain Carbon
Compound two different elements (means two or more)
Acetic acid

17. Shows how many atoms of each element a molecule contains
7. Molecular formula
Shows how many atoms of each
element a molecule contains
Does not tell you about a molecule’s structure
Water
Glucose
Ammonia

18. Examples of molecular formulas
H2O 2 hydrogen
1 oxygen
NH3 1 nitrogen
3 hydrogen
C6H12O6 6 carbon
12 hydrogen
6 oxygen

19. 8. Structural formula Shows how atoms are arranged in a molecule
2-dimensional representation of a molecule’s structure
From structural formulas, scientists can create ball and stick models
We are going to do a laboratory where you are going to get to make ball and stick models of organic molecules
Out of toothpicks and marshmallows!
Read over the laboratory assignment for homework.

20. 9. 3-D model Shows how the atoms are arranged in a molecule
Is able to be moved or turned, allowing you to view the molecule from different angles
3D model