1. Matter, Atoms, Elements A chemistry review

2. What’s matter?  Matter is anything that has mass and volume  Mass is  Volume is  Matter is made up of atoms

3. Atoms  Atoms are the simplest form of matter  The structure of atoms determines the properties of matter  An atom has:  Nucleus  Electron cloud

4. Created by G.Baker www.thesciencequeen.net An atom refresher  An atom has three parts:  Proton = positive ◦ Mass about 1 amu  Neutron = no charge ◦ Mass about 1 amu  Electron = negative ◦ Mass 1/1836 amu  The proton & neutron are found in nucleus  The electrons are in the electron cloud Picture from http://education.jlab.org/qa/atom_model _03.gif

5. Elements  Elements are made of one kind of atom  Elements cannot be broken into simpler substances using normal chemical reactions  Elements cannot be broken into simpler substances using physical reactions  Periodic table of elements!

7. Created by G.Baker www.thesciencequeen.net Periodic Table 8 O Oxygen 16 Atomic Number: Number of protons and it is also the number of electrons in an atom of an element. Element’s Symbol: An abbreviation for the element. Element’s Name Atomic Mass/Weight: Number of protons + neutrons.

8.  Atoms of an element don’t always have the same mass number  Protons are the same!  What’s different?  Isotopes are  Examples: Isotopes Isotope# p+# n o # e-At noMass no Hydrogen-1 Hydrogen-2 Hydrogen-3

9. LecturePLUS Timberlake9 Isotope notation Show the mass number and atomic number Give the symbol of the element mass number 23 Na sodium-23 atomic number 11

10. Atoms all Want: Full outer (valence) electron shell How do they get it? Atoms form compounds Compound: 2 or more atoms chemically bonded together Bond: Force holding atoms together Properties of compound are different from elements

11. Bonding 2 kinds of bond: Ionic Covalent All bonds happen so atoms can have full valence shell!

12. Covalent bonding Covalent bonding: Sharing electron pairs Between nonmetal atoms Makes molecules Sometimes more than one pair is shared Double bond Triple bond

13. Let’s look at an example! Hydrogen! Atno is Number of valence e- Is H happy? NO! What would make the valence shell full?

14. Here’s Oxygen! Atno is Number of valence e- Is O happy? NO! What would make O happy?

15. Bonding! H says let’s share! Another H also shares! Now everyone’s happy! We’ve made a compound!

16. Who’s going to share? Elements in groups 14-16 and H Elements in group 17 and H with themselves

17. Ionic Bonding Ion: A particle with a charge Formed when: Atoms gain or lose e- Gain e- : become negative Lose e- : become positive Metal and nonmetal bond Metals: left side of periodic table Nonmetals: right side of periodic table

18. Forming Ions Let’s think about sodium! Atno is: Na

19. Forming Ions How about chlorine? Atno is

20. Forming Ions What happens? Na loses e- Becomes Na+ Cl gains e- Becomes Cl-

21. Forming Ions What happens? Na+Cl- Opposite charged ions are attracted!