1. Atom The basic building block of all matter. Greek for átomos: undivided Material from: http://www.mdusd.k12.ca.us/foothill/staff/elliott/notes/Atoms.htm http://www.csmate.colostate.edu/cltw/cohortpages/viney_off/atom.jpg

2. A. Parts of an Atom 1. Nucleus: in the center of an atom a. Protons: Positively charged particles in the nucleus Positively charged particles in the nucleus Have the mass of 1 atomic mass unit (1 amu) Have the mass of 1 atomic mass unit (1 amu) b. Neutrons: Neutrally charged particles in the nucleus (no charge) Neutrally charged particles in the nucleus (no charge) Also have mass of 1 amu. Also have mass of 1 amu. p+p+ n

3. A. Parts of an Atom (continued) (continued) 2. Electron Cloud: Outside the nucleus 2. Electron Cloud: Outside the nucleus a. The place you’ll most likely find an electron a. The place you’ll most likely find an electron b. Electrons: b. Electrons: Negatively charged particles found in the cloud Negatively charged particles found in the cloud Have VERY little mass (1/2000 amu) so it’s not included in an atom’s mass. Have VERY little mass (1/2000 amu) so it’s not included in an atom’s mass. e-e-

4. B. Atomic Number 1. The number of protons in an atom. 2. What makes each element unique. 3. The smaller number in an element’s square. 4. When drawing an atom diagram, we usually draw the same number of electrons as protons. 5. What is the atomic number of each element and how many protons & electrons are in each?? 1.0079238.03 12.011

5. C. Atomic Mass 1. It’s the sum of the protons and neutrons in an atom. 2. The unit is: amu (for atomic mass unit). 3. Number of neutrons = (Atomic Mass) – (Atomic Number) 4. What’s the atomic mass of each element? 5. How many neutrons are in each element?? 1.0079 12.011 238.03

6. Open to your “Atoms” notes and copy this: A Diagram of a Nitrogen Atom 2-15-11 7 N Nitrogen 14.01 Atomic Number : Equal to number of protons in one atom, as well as electrons Atomic Mass : Comes from total mass of protons+neutrons (electrons add very little mass) Element Symbol Element Name ++n +nn+n+ n+n+n - - - - - - Nucleus area: Protons (+) & Neutrons (n) 1 st Electron Shell: can hold 2 -e 2 nd Electron Shell: can hold 8 -e Electrons (-e) - e

7. D. Periodic Table of the Elements 1. This lists all elements, by atomic number

8. Summary – Important Things to Remember Atoms contain: Atoms contain: 1.Protons (+): They have a positive charge. Atomic mass = 1 amu Atomic mass = 1 amu # of Protons = Atomic Number # of Protons = Atomic Number 2.Neutrons (n): They have a neutral charge. Atomic mass = 1 amu Atomic mass = 1 amu # of Neutrons = (Atomic Mass) – (Atomic #) # of Neutrons = (Atomic Mass) – (Atomic #) 3. Electrons (-): They have a negative charge. Very small mass & are located in different energy level shells Very small mass & are located in different energy level shells # of Electrons = Number of protons # of Electrons = Number of protons

9. D. Atom Bonds 1.Covalent Bonds Electrons are shared between atoms Electrons are shared between atoms Example: Water molecules are made from 2 Hydrogen atoms and 1 Oxygen Atom. Each Hydrogen atom has 1 electron. They are then shared with the Oxygen atom because it can hold 2 more electrons in its outside 2nd shell B. Ionic Bonds Example: Water molecules are made from 2 Hydrogen atoms and 1 Oxygen Atom. Each Hydrogen atom has 1 electron. They are then shared with the Oxygen atom because it can hold 2 more electrons in its outside 2nd shell B. Ionic Bonds 2. Ionic Bonds Electrons are transferred from one atom to another Electrons are transferred from one atom to another Example: To make table salt (chemically called Sodium Chloride), a Sodium atom gives/transfers its 1 electron that is in its 3rd electron shell to a Chlorine atom. Sodium is happy as its outside 2nd shell is full with 8 electrons. Chlorine’s 3rd shell has 8 electrons and is also happy. Example: To make table salt (chemically called Sodium Chloride), a Sodium atom gives/transfers its 1 electron that is in its 3rd electron shell to a Chlorine atom. Sodium is happy as its outside 2nd shell is full with 8 electrons. Chlorine’s 3rd shell has 8 electrons and is also happy.

10. Covalent Bonds

12. Atom Bonds B. Ionic Bonds Electrons are transferred from one atom to another Electrons are transferred from one atom to another Example: To make table salt (chemically called Sodium Chloride), a Sodium atom gives/transfers its 1 electron that is in its 3rd electron shell to a Chlorine atom. Sodium is happy as its outside 2nd shell is full with 8 electrons. Chlorine’s 3rd shell has 8 electrons and is also happy. Example: To make table salt (chemically called Sodium Chloride), a Sodium atom gives/transfers its 1 electron that is in its 3rd electron shell to a Chlorine atom. Sodium is happy as its outside 2nd shell is full with 8 electrons. Chlorine’s 3rd shell has 8 electrons and is also happy.

13. Ionic Bonds