1. Atomic Structure

2. Atomic Structure Elements the “stuff” of which all things are made
C, H, O and N most common in living things
90% of all atoms on Earth are H

3. Atomic Structure Element = a distinct type of atom Hydrogen (H)
Gold (Au)

4. Atomic Structure An atom is made up of 3 particles: Protons (p+)
Neutrons (n0)
Electrons (e-)

5. Protons (p+) Charge - Positive Location - nucleus
Mass – 1 atomic mass unit (amu)

6. Atomic Number
= # of protons an element has
Atomic Number 2 He
4.003

7. Atomic Number e.x. the atomic number of Hydrogen
is 1 because it has 1 proton

8. Atomic Number What is the atomic number of Lithium? 3
How many protons does it have?
What is the atomic number of carbon? 6

9. Charge -none (Neutron – Neutral) Location - nucleus
Neutrons (n0)
Charge -none (Neutron – Neutral)
Location - nucleus
Mass – 1 atomic mass unit (amu)
Neutrons

10. Neutrons Isotope = an atom of a certain element that
has a different # of neutrons
than other atoms of that element
e.g. Most C atoms have 6 neutrons (C12)
but some have 8 (C14)

11. Isotopes For what is Carbon 14 used? carbon dating
(radiometric dating)

12. Atomic Nucleus
The nucleus contains most of the atomic mass
protons + neutrons = Atomic
mass

13. Review 1. What does F stand for? Fluorine
2. What is its atomic number ? 9
3. How many protons does it have?
4. How many electrons does it have?

14. Review 5. What is Fluorine's atomic mass? 19
6. How many neutrons does it have? 10
atomic mass - protons = neutrons
19 – 9 = 10 neutrons

15. Electrons (e-) Charge - Negative
Location – in orbit in electron shell or cloud around the nucleus
Mass – negligible (too small to count!)
(9.1 X kg)
# electrons = # of protons
(for now)

16. Electrons Valence electrons- electrons in outermost shell of atom
Determine the properties of an element e.g. taste, texture, appearance, color
Determine how an element reacts chemically

17. Models of the Atom
Studies done by Chemists for years has lead to different models of the atom
Earnest Rutherford
Gold foil experiment-discovered nucleus
Neils Bohr
Schrodinger and Heisenburg
Probability Cloud
Louis de Broglie –moving matter possesses a wavelength

18. Gold Foil Experiment

19. Models of the Atom Bohr model (planetary model) -Neils Bohr in 1911
Electrons orbit the nucleus with different energies (on a path, like planets orbit the sun)