1. October 29 th, 2015 Start Atomic Structure & Periodic Table Bell Ringer Get homework out on your desk.

2. Today’s Purpose: 1.Describe the present model of the atom.

3. Matter and atoms Matter: Anything that has mass and takes up space. All matter is made up of atoms.

4. Matter and atoms Atom: Basic building block of matter Cannot be broken down further without changing the properties of that element The smallest unit of an element

5. Different types of atoms are called elements. All matter is made of the atoms of approximately 118 elements. Iron 5% Earth’s Crust Oxygen 47% Silicon 28% Aluminum 8% Other 12% Humans Other 3% Nitrogen3% SOURCE:CRCHandbookof Chemistry andPhysics Oxygen 61% Carbon 23% Hydrogen 10% Atom Concentrations by Mass

6. Chemical symbols A chemical symbol is an abbreviated way to write the name of an element. For example: C = H = Fe =Iron Hydrogen Carbon

7. Chemical symbols Chemical symbols always consist of one capital letter or a capital letter plus one or two small letters. CClCSCs

8. neutron electron cloud nucleus proton Atoms are made of protons, neutrons, and electrons. Nucleus – the central region of an atom where most of the atom’s mass is found in protons and neutrons.

9. Atoms are mostly empty space. The radius of a atom is about 100,000 times larger than the radius of its nucleus. If a basketball represented a nucleus…that atom would have a radius of 7.5 miles!

10. Protons: Positive (+) charge, mass = 1, indicates identity of atom Neutrons: Neutral (0) charge, mass = 1 Electrons: Negative (-)charge, mass = 1/2000 Found inside nucleus Found outside nucleus

11. B 5 Boron Atomic Number = Number of protons Boron has 5 protons

12. Mass Number = Protons + Neutrons

13. Protons = 7 + Electrons = ? N +3 7 4 Charge = +3

14. Protons = 35 + Electrons = ? Br 35 36 Charge = -1

15. Protons = 25 + Electrons = ? Mn 25 Charge = 0

16. Matter and atoms Nucleus (+ charge) Electrons (- charge) - “orbit” the nucleus Proton (+) Neutron (No charge)

17. Models of the atom

18. Assignments Book reading chapter. Atomic Structure (ws) Quiz on elements Wednesday, November 4 th