1. KEY CONCEPT All living things are based on atoms and their interactions.

2. An atom is the smallest basic unit of matter.
Please draw and label an atom on pg. 10 (don’t take up the whole page!)
energy
level

3. Fun Fact
It would take you over 1,000,000,000,000 (1 Trillion) years to count the number of atoms in a single grain of sand

4. Although there is a huge variety of matter on Earth, all atoms share the same basic structure…
Protons- in the nucleus. Positively charged (+)
Neutrons-in the nucleus. Neutrally charged (no charge)
Electrons-much smaller particles on the outside of the nucleus on the energy level. Negatively charged (-)

5. Energy levels: electrons are located here
Energy levels: electrons are located here. Inner levels only have 2 electrons, other levels hold up to 8.
Oxygen atom (O)
Nucleus: 8 protons (+) 8 neutrons
outermost energy level: 6 electrons (-)
inner energy level: 2 electrons (-)
Energy Levels

6. What can you notice about these elements’ proton numbers and electron numbers?
Iron
50 P
50 E
69 N
Tin
79 P
79 E
118 N
Gold
Proton # = Electron # !!!!
Aluminum
13 P
13 E
14 N

7. Gold electrically neutral!!!! +5 + (-5) = ??? +5 + (-5) = 0
*Atoms have equal numbers of positively charged protons and negatively charged electrons so they are...
electrically neutral!!!!
+5 + (-5) = ???
+5 + (-5) = 0
79 P
79 E
118 N
Gold

8. An element is one or more atoms of the same type.
It cannot be broken down into a simpler substances
Ex: Oxygen, Hydrogen, Iron…
gold
aluminum

9. Ex: Gold has 79 protons no matter what
Atoms of different elements differ in the number of protons they have. The proton # never varies.
26 P
26 E
30 N
Iron
50 P
50 E
69 N
Tin
79 P
79 E
118 N
Gold
Ex: Gold has 79 protons no matter what
Aluminum
13 P
13 E
14 N

10. A molecule is two or more atoms held together by covalent bonds.
Hydrogen

11. A compound is made of 2 or more different elements bonded together in a certain ratio. Ex: H20
water (H2O)
-carbon dioxide (CO2)
Carbon dioxide (CO2) O H _ + O C O

12. O O All compounds are molecules NOT all molecules are compounds Ex: O2
* Remember compounds are composed of 2 different elements

13. Atoms Positive charge Proton # identifies element
Nucleus: most mass of atom
No electrical charge
Neutron
About same size as proton
Atom: smallest basic unit of matter
Is surrounded by
Negative charge
Electrons
# equals # of protons
Cloud: most volume of atom
Forms chemical bonds
Inner level only 2 Protons
Energy Levels
Other levels up to 8 Protons
Tries to fill outer level

14. Q: Because all atoms are made of the same types of particles (protons, neutrons, and electrons), what difference among atoms makes one element different from other elements?
Aluminum Iron Tin
A: Atoms of different elements differ in the number of protons they have.

15. Understanding how an ion forms ionic bonds and covalent bonds is important because ions play large roles in organisms.
They are important in all biological processes. A few examples are:
They play a role in muscle contraction and cell shape
Chloride (Cl-) is a chemical the human body needs for metabolism (the process of turning food into energy)
Calcium ions (Ca2+) are necessary for every muscle movement in your body

16. An ion is an atom that has gained or lost one or more electrons (-)+
11 P (+)
10 E (-)
17 P (+)
18 E (-)
11 p
17 p

17. -
Positive Ions: If an atom has few electrons in its outer energy levels it tends to lose those electrons and become a POSITIVELY charged ion
Negative Ions: If an atom has a nearly full outer energy level it tends to gain electrons and become a NEGATIVELY charged ion
Energy level

18. *An ion forms because an atom is more stable when its outermost energy level is full.

19. *An ion forms because an atom is more stable when its outermost energy level is full.

20. Ionic bonds form between oppositely charged ions. Dissolve in H2O.
“Opposites Attract!!!!”
Now we have salt!!!!

21. H2O covalent bonds Share electrons in outer energy level
Can have multiple bonds
Strong bonds
covalent
covalent
H2O
Aka
Water!
Hydrogen

22. “Science Matters”
Draw the atoms that are described below. Remember what you have learned about where each one of the particles are located in an atom. Use red for protons, black for neutrons, and blue for electrons.
1. Nitrogen:
Protons: 7
Neutrons: 7
Electrons: 7

23. “Science Matters”
Draw the atoms that are described below. Remember what you have learned about where each one of the particles are located in an atom. Use red for protons, black for neutrons, and blue for electrons.
1. Nitrogen:
Protons: 7
Neutrons: 7
Electrons: 7

24. What distinguishes one element from another?
2.1 Review
What distinguishes one element from another?
Describe the formation of an ionic compound.
What is the difference between an ionic bond and a covalent bond?
How does a molecule differ from an atom?