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Unit 1 Chemistry
Review of Basic Chemistry
name charge symbol mass location
proton
electron
neutron
+
-
o
p+
e-
no
1 amu
1 amu
1/1837 amu
nucleus
nucleus
orbiting the nucleus
1 amu = 1.67 x 10 -24 g
A: Subatomic ParticlesAtoms are composed of protons, electrons, and neutrons.
Electrons carry a negative charge and move around the nucleus.
The nucleus is made up of positively charged protons, and neutrons, which have no electrical charge.
Size of 1 Atom:An atom is around 0.1 nanometer, or 100 picometers.
http://www.powersof10.com/film
B: Structure of Atoms
• In a neutral atom, the number of protons (atomic number)= the number of electrons.
• The mass number = # protons + # neutrons.
• Each electron orbital can hold a certain number of electrons:
1st orbital can hold only 2 e- (inner most)
2nd orbital can hold only 8 e-
3rd orbital can hold only 8 e-
4th orbital can hold only 18 e-
Atomic structure of a fluorine atom:
Electrons do NOT orbit the nucleus like planets orbit the sun
Rather, they occupy “areas of probability” around the nucleus
Element Number of Neutrons
Number of Electrons
Number of Protons
Mass Number
11 23
6 12
19
16
uranium
61 47
1112sodium
66carbon
fluorine 9910
16sulphur 32169292 238146
47 108silver
How many electrons does a sodium atom have in its outer orbit?
How many electrons does carbon have in its outer orbit?
How many neutrons does a nickel atom have?
How many electrons does hydrogen have?
How many electrons does helium have in its outer orbit?
Does oxygen have a complete outer electron orbit?
one
four
31
one
two
No – 6 electrons
The Periodic Table
Constructing a “Periodic Table”
look at each animal and make brief notes about its appearance
when we have seen all of the animals, you will arrange them into logical groups based on ?
tiger
1 m
eland
1 mzebra
1 m
wild horse
1 m
coyote
1 m
impala
1 m
jackal1 m
wildcat
0.3 m
lynx
1 m1 m
kudu
wild ass
1 m
1 m
timberwolf
1 m
gazelle
leopard
1 m
now put these animals into two logical groups
now divide the two groups each into two subgroups
then organize them in the same pattern within each group
wildcat lynx
leopard
tiger
wild ass
zebrawild horse
gazelle
impala
kudu
eland
jackal
coyote
wolf
we can arrange them into groups by appearance and then within groups, by size
wildcat lynx
leopard
tiger
wild ass
zebrawild horse
gazelle
impala
kudu
eland
jackal
coyotetimberwolf
wildcat lynx
leopard
tiger
jackal
coyotetimberwolf
wild ass
zebrawild horse
gazelle
impala
kudu
eland
carnivoresherbivores
take lifegive up life
Not all herbivores are equal, some give up life more easily
Not all carnivores are equal, some take life more easily
now let’s relate this to the real
Periodic Table of Elements
C: The Periodic Table
• The periodic table is made of three types of elements;
1. metals (give up electrons)
2. non-metals (take electrons)
3. metalloids (bit of both)
boron, silicon, germanium, arsenic, antimony, tellurium, polonium
A chemical group/family is a vertical column of elements that have similar physical and chemical properties.
Column 1: alkali metals
Column 2: alkaline earth metals
Column 3-11: transition metals
Column 17: halogens
Column 18: noble gases/inert gases
Two Rows at Bottom: rare earth metals
On the periodic table there are 18 vertical groups.
based only on atomic properties the Periodic Table would look like this!!
for convenience, we pull out the rare earths so the Periodic Table looks like what we see
Periods
•Periods are horizontal rows of elements.
•The first period (row) contains 2 elements.
•The second period (row) contains 8 elements etc.
•The properties of an element gradually change across a period.
•The size of an atom gets smaller as you move across a period.
Valence electrons:• Electrons that occupy the outermost orbital are
responsible for the chemical behavior of the element.
sodium atom
D: Lewis Diagrams• Lewis diagrams show the number of electrons in the
outermost orbit only.
R1
2
3
45
67
8
Take out a piece of paper and make Lewis diagrams for
B, Be, C, Cl, F, H, He, Li, Mg, N, Na, O, P, S