Atomic Structure

To discuss the evolution of the atomic model Aim 1 To discuss the evolution of the atomic model

basic building block of matter/single unit of an element Atom basic building block of matter/single unit of an element cannot be broken down chemically

Dalton (1808)- Father of the atomic theory All matter is made up of small particles called atoms 2. Atoms of the same element are identical

3. Atoms of different elements are different 4 3. Atoms of different elements are different 4. Atoms cannot be broken down

5. Atoms of different elements combine in simple whole-number ratios to form chemical compounds 6. In chemical reactions, atoms are rearranged (combined OR separated)

****CANNONBALL THEORY/MODEL**** Representation ****CANNONBALL THEORY/MODEL****

Thomson 1. Discovered SUBATOMIC PARTICLE called the ELECTRON 2. Concluded that electrons are SMALL and NEGATIVELY CHARGED

**** PLUM PUDDING THEORY/MODEL**** Representation **** PLUM PUDDING THEORY/MODEL****

Video https://www.youtube.com/watch?v=O9Goyscbazk

Rutherford Conducted the GOLD FOIL EXPERIMENT where he BOMBARDED a thin piece of GOLD FOIL with POSITIVE PARTICLES

2. Expected all particles to pass straight through foil 2. Expected all particles to pass straight through foil. Most passed through, but some were severely deflected.

3. He concluded that because most of the atoms went through that the atom was MOSTLY EMPTY SPACE and that because some of them were deflected, that the atom has a DENSE, POSITIVELY CHARGED CENTER called the nucleus!

Diagram of Experiment

LED TO… ****** NUCLEAR THEORY/MODEL******

NEILS BOHR (1913) Bohring! Electrons travel AROUND the nucleus in well-defined (FIXED) paths called ORBITS Each electron has a unique amount of energy: higher # shell=more energy. This is its fingerprint.

Representation

Wave-Mechanical/Cloud Model Electrons have distinct amounts of energy and move in areas called ORBITALS MANY SCIENTISTS have contributed to this theory

Orbitals an area of HIGH PROBABILITY for finding an ELECTRON (not a circular path) Electrons DO NOT TRAVEL IN FIXED PATHS

Representation: Generally called Fuzzy Cloud

To understand the vocabulary of the periodic table! Aim 2 To understand the vocabulary of the periodic table!

VOCABULARY (OF THE PERIODIC TABLE) Element Symbol = the letter(s) used to identify an element Only one letter will be capitalized

Atomic # = the number of protons in EVERY ATOM of the element NEVER CHANGES!!!

Atomic Mass = AVG. mass of all the isotopes of an element

Electron configuration = number of Oxidation #’s = possible charges an atom of an element can have Electron configuration = number of electrons in each energy level; add the numbers to get the total # of electrons

Subatomic Particles Subatomic Particle Charge Relative Mass Location Symbol How to Calculate Proton Neutron Electron

Practice Symbol Protons Neutrons Electrons Atomic Number Mass Number Nuclear Symbol Cl-35 C-12 Ar-40 O-16

Aim 3 To calculate the average atomic mass using all isotopes of a given element

Isotopes? ISOTOPE = atoms of the same element with different mass #’s; same atomic #

Nuclide: a way to express an isotope Nuclide: a way to express an isotope. It must include the identity of the element AND MASS Examples: Carbon-14 OR 14 C 6

EXAMPLE 1: ISOTOPES OF CARBON (C-12, C-13, & C-14)

EXAMPLE 2: ISOTOPES OF URANIUM (U-238, U-240)

Aim 4 To draw Bohr diagrams to represent the size of an atom and to locate electrons

bohr BOHR DIAGRAMS (one method for expressing electron location in an atom or ion); ALL ELECTRONS MUST be drawn  BOHRing

practice

The last number in the electron configuration Valence electrons Valence electrons are electrons found in the outermost shell or orbital of an atom The last number in the electron configuration

Inner electrons (all non valence electrons) Kernel electrons Inner electrons (all non valence electrons)

Practice Chlorine Nitrogen Potassium Sodium

To draw electron dot diagrams to predict behaviors of an atom. Aim 5 To draw electron dot diagrams to predict behaviors of an atom.

Lewis (Electron) dot diagrams Lewis Electron Dot Diagrams: Only illustrate VALENCE ELECTRON CONFIGURATION

rules 1. Write the element’s symbol 2. Retrieve electron configuration from Periodic Table. The last number in the configuration is the NUMBER OF VALENCE ELECTRONS

Aim 6 To differentiate between atoms and ions in order to determine the chemical properties of matter.

ATOMS (NEUTRAL) VS. IONS (CHARGED) Vocabulary Term Definition Example/Diagram Atom Ion (aNion) Ion (ca+ion)