Atomic Structure Unit 3

History of the Atom Watch the Brain Pop on Atomic Model!

Atomic Structure Electrons- outside the nucleus Protons Neutrons + + N N - Neutrons Outside the nucleus

Complete the following table: Subatomic Particle Location Charge Mass Electron Proton Neutron

Complete the following table: Subatomic Particle Location Charge Mass Electron Electron Cloud (-) 0 amu (teeny tiny!) Proton Nucleus (+) 1 amu Neutron Neutral

Reading the Periodic Table * Atomic #: The number of _protons_ in an atom. It equals the number of _electrons_ in a neutral atom. * Mass number = __protons__ + neutrons * # of neutrons = _Mass_#___ - ___atomic number_____ * Atomic Mass: The _average__of all naturally occurring isotopes.

Observe the models of atoms at your Lab stations. Use the results and your periodic table to complete the chart and the following questions. Homework: Complete page 6

NOTES: Isotopes and Ions Warm-up:

Isotopes: Isotopes - is a version of an atom with the same number of PROTONS, but different number of NEUTRONS. -If an atom is an isotope you name it using the element name followed by the mass number. * Ex: carbon – 12 and carbon -14 - Writing Isotope Symbols: Write the atomic symbol for the element To the top left of the symbol write the mass # of the isotope. Beneath that (to the bottom left of the symbol). Write the atomic number of the element.

Ex: Label the following Carbon-14 is written like this: C Mass # 14 Element Symbol 6 Atomic #

C and C 14 12 6 6 Isotope Examples: How many protons does Carbon-14 contain? How many protons does Carbon-12 contain? 6 How many neutrons does Carbon-14 contain? How many neutrons does Carbon-12 contain? 14-6 = 8 12-6= 6

Ions are charged atoms (+ or -) * Atoms as a rule are all neutral in charge, meaning that the number of protons and electrons in the atoms are equal. Ions: Ions are charged atoms (+ or -) Formed when an atom GAINS or LOSES electrons

Ions Examples Lithium - 7 + Protons: 3 Neutrons: 4 Charge: 1+ Cations Positively (+) charged atoms Form by LOSING electrons Usually formed by metals Examples Lithium - 7 + Protons: 3 Neutrons: 4 Charge: 1+ Electrons: 2

2- Ions Protons: 16 Neutrons: 16 Charge: 2- Electrons: 18 Anions Negatively (-) charged atoms Form by GAINING electrons Usually formed by nonmetals Examples Sulfur - 32 2- Protons: 16 Neutrons: 16 Charge: 2- Electrons: 18

Page 9 -10 Complete the table as directed on Pg. 9. Complete the chart and answer the questions on Pg. 9 in group of 2 (no larger!). Homework: Pg. 10

Atom# Isotope Symbol Atom name with mass # #Protons #Neutrons #Electrons Atomic Number Mass Number Neutral/Isotope/Ion Charge 1   Neutral 2 3 4 5 6 7 8 9 10 11 12

Isotopes and Average Atomic Mass Isotopes and Average Atomic Mass * Compare & contrast Mass Number and Atomic Mass:

Atomic Mass Calculations Atomic mass is the weighted average of the masses of all naturally occurring isotopes. Atomic Mass= Σ[(Percent Abundance) x (Mass of Isotope)] Σ = take the sum of; add them all up at the end! Sample Calculations together.. 

Atomic Structure- Inside the Nucleus Protons Positively (+) charged particles Equal to the atomic number Identity of atoms is based on # of protons in Nucleus Contribute to the mass of the atom Proton mass = 1amu amu= atomic mass unit

Atomic Structure- Inside the Nucleus Neutrons Neutral particles (no charge) Help hold nucleus together; contribute to stability Neutrons + Protons= mass number Neutron mass = 1amu

Atomic Structure- Outside the Nucleus (Electron Cloud) Electrons Negatively (-) charged particles Responsible for the CHEMICAL PROPERTIES of the atom In a neutral atom (no charge), protons=electrons Very little mass ~0 amu

Reading the Periodic Table Elements Atomic number 6 = # Protons (element identity!) C Element Symbol Last page of notes!!! Students will have to flip their packets to the back to complete, before returning to the back of page 2 to complete their content frame.  = weighted average of isotope atomic masses 12.01 Atomic Mass Carbon

Complete the following table: Complete Symbol Mass Number Atomic Number Protons Neutrons Electrons 16 14 Se 70 34

Si 14 16 70 34 Se 14+16 = 30 70-34 = 36 30 14 70 34 Complete Symbol Mass Number Atomic Number Protons Neutrons Electrons Si 14+16 = 30 14 16 Se 70 34 70-34 = 36 30 14 70 34

+= = Cations