Atomic Structure and Periodic Table Notes

Atoms are the smallest particle of an element the “Building Blocks” 1. What are Atoms? Atoms are the smallest particle of an element the “Building Blocks”

2. 400 BC Democritus was the first scientist to suggest that all matter is composed of tiny, individual particles called atoms. (Atomos)

An element is matter made up of only ONE type of atom. 3. Elements are made up of atoms. Atoms are the smallest particle into which an element can be divided and still retain its identity. An element is matter made up of only ONE type of atom.

4. The Atomic Theory was proposed by John Dalton in the late 1700’s 4. The Atomic Theory was proposed by John Dalton in the late 1700’s. This theory was based on the experimentation and data of other scientists.

5. Atomic Theory All matter is made of atoms Atoms cannot be divided Atoms of a particular element are exactly alike Atoms can join with other atoms to create new substances .

5. Since then, other scientist have expanded on our understanding of atoms in the following ways. -1897 JJ Thompson used the cathode ray tube to find negative particles within the atom , which he named electrons. (He called his model the Plum pudding model)

-Early 1900’s Rutherford directed a beam of positively charged particles through a piece of Gold. He then created a new atomic model with a dense positively charged Nucleus. ( The Nuclear Model)

- 1913 Bohr Further studied the atom and proposed an atomic model with a dense Positive nucleus with Electrons orbiting around in definite pathways. (The planetary Model)

- 1926 Schrödinger stated that electrons can only exist in specified energy states. (Electron Cloud Model) - 1932 Chadwick discovered neutral particles in the nucleus of an atom called Neutrons.

6. Today’s model of the atom is called a Cloud model which includes a dense nucleus made up of Protons and Neutrons. The Electrons occupy a region of space outside of the nucleus and orbit in an irregular manner

Proton Positive Nucleus 1 AMU Electron Negative Electron cloud Name of the particle Charge of the particle Location Size/mass Proton Positive Nucleus 1 AMU Electron Negative Electron cloud Almost 0 Neutron Neutral /No charge

7. After watching the WKRP video on the parts of an atom- List 3 parts of an atom and the way each part was described. Protons- “Pro’s”- found in the nucleus are positive Electrons- “elected ones” are outside the nucleus- are negative Neutrons- “New Boys” found in the nucleus – are neutral

8. Protons- have a Positive charge, and each has a mass of one AMU ( atomic mass unit) 9. Neutrons – have NO charge ( sometimes stated as Neutral or Zero charge), and each also has a mass of one AMU (atomic mass unit) 10. Electrons- have a Negative charge, and a very tiny mass of .0005 AMU’s. The mass of electrons are so small that they are usually ignored when adding up the mass of the entire atom ( almost 0)

11. Atoms that are electrically NEUTRAL will have the same number of Protons and Electrons. 12. The atomic mass is the total number of Protons & Neutrons in an atoms Nucleus.

APE Atomic # = Protons = Electrons 13. The Atomic # of an element tells you the number of protons. In a neutral atom it also tells you the number of electrons. APE Atomic # = Protons = Electrons

MAN Mass # - atomic # = # of Neutrons 14. The rounded Atomic Mass of an element tells you the number of Protons and Neutrons in an atom. Therefore, the rounded atomic mass minus the number of protons (atomic #) tells you how many Neutrons are present in an atom of a particular element. MAN Mass # - atomic # = # of Neutrons

A=P=E M-A=N

15. We use Bohr models to understand Atomic structure and the reactivity of atoms. When creating a Bohr the following rules apply. Protons an Neutrons are located in the nucleus. Electrons are arranged in energy levels/orbitals 1st energy level /orbital holds up to 2 electrons 2nd energy level /orbital holds up to 8 electrons 3rd energy level /orbital holds up to 18 electrons (Happy with 8)

Example Argon Atomic #_______

16. There are 3 major groups on the periodic table Metals – shiny, malleable, ductile, good conductors , usually solid – on the left side of the periodic table Non-metals- solid, liquid or gas, not good conductors – on the right side of the periodic table. Metalloids- share properties of metals and nonmetals– found along the zig-zag line (stair step line) on the periodic table

17. Dimitri Mendeleev- a Russian inventor and Chemist developed the first Periodic Table of elements (although other scientists made contributions)

18. Write down 5 things about the element OXYGEN 18. Write down 5 things about the element OXYGEN. Make sure you use characteristics from the periodic table. 1. 2. 3. 4. 5.