1. Atomic Structure

2. What is an atom?
An atom is the smallest part of matter that keeps unique properties.
Ex: Iron
The charge on an atom is ALWAYS ZERO!!!!!

3. Subatomic Particles Atoms are made of three smaller parts Protons
Neutrons
Electrons

4. H Protons Where: In the Nucleus Relative mass: 1 AMU
Charge: Positive +
Atomic Number = the number of protons
All the atoms of an element have the same number of protons.
Hydrogen 1 H
1.0079

5. Atomic Number Practice
What’s the atomic number for lithium?
What’s the atomic number for nitrogen?
What’s the atomic number for zinc?
What’s the atomic number for chlorine?

6. Neutrons Where: In the nucleus Relative mass: 1 AMU
Charge: 0 (No charge)
The same element can have different numbers of neutrons
The atomic mass – atomic number = # of neutrons

7. H Atomic Mass The average mass of one atom of an element.
Hydrogen 1 H
1.0079
The average mass of one atom of an element.
The atomic mass is equal to the number of protons + the number of neutrons.

8. Atomic Mass Practice
Find the atomic mass of each of the following elements
Argon
Tin
Calcium
Yttrium

9. Finding the Number of Neutrons
Atomic Mass – Atomic Number = # of Neutrons

10. Electrons Where: Outside the nucleus in orbitals
Relative mass: 1/2000 AMU
Charge: Negative (-)
The number of electrons cause the chemical properties of an atom

11. Electrons:
Atoms of the same element can have different numbers of electrons.
The atomic number is equal the number of electrons in an atom.

12. Electron Practice How many electrons are in a atom of nitrogen?
How many electrons are in an atom of chromium?

13. Shape of an Atom
An atom has a tightly packed nucleus containing protons and neutrons. The electrons are located in an orbital outside of the nucleus.