1. Atomic Structure

2. The Atom Smallest form of an element that still retains that elements properties Basic building block of matter Made of:  Protons  Neutrons  Electrons

3. The Atom Composed of:  Nucleus  Electron Cloud

4. The Nucleus Positively charged Protons and neutrons  Protons – positively charged  Neutrons – neutrally charged  Neutrons act like glue

5. The Electrons Negatively charged Occupy the “Electron cloud” surrounding the nucleus Arranged into shells or orbitals Electrons are NOT moving in perfect orbits around the nucleus. The electron movement is unpredictable Cloud gives us approximate location of where electrons are

7. Subatomic Particles LocationChargeMassSpecial Fact ProtonsNucleusPositive (+) 1 amu Same as neutron Number of protons determines the identity of the element NeutronsNucleusNeutral1 amu Same as proton ElectronsElectron Cloud Negative (-) 0.00054 amu (1/2000 th mass of a proton or neutron) Electron cloud takes up 99.9999999% of the volume of the atom

9. Properties of Atoms Atomic Number Mass Number Average Atomic Mass

10. INSIDE THE SQUARES…

11. Or you might see it as…. Carbon- 12 Mass number

12. Atomic Number Number of protons in the nucleus of an atom Each element has its own specific atomic number In a NEUTRAL ATOM, this is also the number of electrons

13. (Average) Atomic Mass An average mass of each of the different isotopes found for that element in nature For example, Chlorine has 2 different isotopes Each one has 17 protons and a different number of neutrons (This is what an isotope is. More on that later) If you take the average atomic mass of every single chlorine atom that exists, the average mass will be 35.453 amu

14. Mass Number Mass number is the mass of a SPECIFIC isotope of an atom. It is the SUM of the protons and neutrons in the nucleus Mass Number = (# of neutrons) + (# of protons) Mass Number = Atomic Mass It is not the average unless we say AVERAGE How do we find # of neutrons?

15. So how do I know what the Mass Number is? One of two ways: 1) Give you the mass number or the neutrons in a table. If I don’t give it to you, get the rounded # off the PT 2) Tell you in the symbol. A) Isotope Notation: B) Name: Sodium-23

16. Figuring out some element parts… ElementSymbolAtomic #ProtonsNeutronsMass # Boron-11B Carbon - 12 66 Magnesium - 23 1223 Copper- 64 2935 20

17. Figuring out some element parts… ElementSymbolAtomic #ProtonsNeutronsMass # Boron-11B55611 Carbon -12C66612 Magnesium-23Mg12 1123 Copper-64Cu29 3564 ????20?