Transcript Parts of an Atom - Science Class Rocks!

Parts of an Atom
• Most of the Atoms contain particles
• There are 3 subatomic particles
–
–
–
•
•
Protons
Neutrons
Electrons
Protons and neutrons are found in the nucleus
Electrons are found in the outer shells
23
Na
11
• Atomic number = number of protons in the
nucleus, bottom number above = 11
•Atomic mass = mass of protons and neutrons in the
nucleus, top number above = 23, always larger
•Protons = positively charged particles in nucleus
•Neutrons = neutral particles in nucleus
•Electrons = negatively charged particles outside nucleus
Isotope
•
Same atomic number but different atomic mass
or different number of neutrons
Which one is an isotope of Na?
11
12
11
22
Na
23
Na
11
Na
24
Na
23
Drawing an atom
• Only 2 electrons can fit on the inner most
energy level.
• Only 8 electrons can fit on the second
energy level.
• The electrons on the outer most energy level
are called valence electrons
Draw an atom of Nitrogen:
+= 7
N= 7
Protons = 7
Neutrons = 7
Electrons = 7
Draw an atom of Boron:
Protons = 5
+= 5
Neutrons = 6
N= 6
Electrons = 5
Charge
• What is the charge of an atom with 6
protons and 8 electrons?
-2
• What is the charge of an atom with 5
protons and 4 electrons?
+1
• What is the charge of an atom with 9
protons and 9 electrons?
0
Superscript and Subscript
• Superscript = Number of molecules in an
compound
– Ex
4NaCl = 4Na AND 4 Cl’s
•Subscript = number of atoms of an element in a
molecule or the ratio of elements in a compound.
•Ex
CO2 = 1 C and 2 O’s
Types of Reactions
• Na + Cl = NaCl
This is a synthesis
reaction because the elements ADD together
•CO2 = C + O2
This is a
decomposition reaction because the elements
are TAKEN APART
•NaCl + LiF = NaF + LiCl
This is a
replacement reaction because the elements REPLACE
each other.
Balancing Equations
• You should have the same amount of each
element on each side of the reaction
• For example C6H12O6 = 6C + ______ H2O.
–Answer: C6H12O6 = 6C + 6H2O
Mixtures and Compounds
• Mixtures = two or more substances that are
put together but NOT chemically combined
– Ex: chocolate milk
• Compound = two or more substances that are
chemically combined
• Ex: carbon dioxide
CO2
Types of Mixtures
• Solution = a very well mixed mixture, having the
same properties throughout
– Ex: salt water
• Suspension = a mixture in which particles can be
seen and easily separated by settling or filtration
- Ex: muddy water
• Colloid = a mixture with small undissolved particles
that do not settle out
Ex: milk