Day 16

Context

So far we have discussed science in general and looked at some specific physical phenomena. We have also applied conditional arguments to help us identify and see the connection between variables. We will now begin a journey toward understanding a sophisticated science concept: intermolecular forces. We will start from the beginning by looking at matter, elements and physical and chemical changes.

Explanation

Video Links
Video Popup
Class Video

Understanding much of the world around us requires a basic knowledge of chemisty which is a major branch of physical science. Today we will address matter and elements, physical and chemical changes, a first look at the periodic table, and talk about some interesting chemical reactions.

After this class you should be able to:

Some Initial Questions

Physical and Chemical Changes

Chemical changes occur when a chemical reaction takes place. In chemical reactions two or more atoms or molecules combine or rearrange themselves to create new substances. The new substance has different properties from the atoms or molecules that are reacting. The reacting substances are call the reactants and the new substances are called the products. So, in a chemical change you go from products to reactants.

A chemical change, then, is a change that produces a new substance.

In physical changes no new substance is formed. An example would be when something changes from one phase, like liquid, to another phase, like gas. When water evaporates it is a physical change because the water molecules are H2O when they are in the liquid phase and they are still H2O when the go out into the air making the air more humid.

The Periodic Table - A First Look

What makes the periodic table periodic?

Here is the Periodic Table of the Elements. I also have a link to an interactive Periodic Table.

Periodic Table of the Elements
1
H
1.01		 Click on the heading for an interactive Periodic Table1
H
1.01		2
He
4.00
3
Li
6.94		4
Be
9.01		 5
B
10.08		6
C
12.01		7
N
14.01		8
O
16.00		9
F
19.00		10
Ne
20.18
11
Na
22.99		12
Mg
24.31		 13
Al
26.98		14
Si
28.09		15
P
30.97		16
S
32.06		17
Cl
35.45		18
Ar
39.95
19
K
39.10		20
Ca
40.08		 21
Sc
44.96		22
Ti
47.88		23
V
50.94		24
Cr
52.00		25
Mn
54.94		26
Fe
55.85		27
Co
58.93		28
Ni
58.69		29
Cu
63.55		30
Zn
65.38		 31
Ga
69.72		32
Ge
72.59		33
As
74.92		34
Se
78.96		35
Br
79.90		36
Kr
83.80
37
Rb
85.47		38
Sr
87.62		 39
Y
88.91		40
Zr
91.22		41
Nb
92.91		42
Mo
95.94		43
Tc
(98)		44
Ru
101.1		45
Rh
102.9		46
Pd
106.4		47
Ag
107.9		48
Cd
112.4		 49
In
114.8		50
Sn
118.7		51
Sb
121.8		52
Te
127.6		53
I
126.9		54
Xe
131.3
55
Cs
132.9		56
Ba
137.3		 71
Lu
175.0		72
Hf
178.5		73
Ta
180.9		74
W
183.9		75
Re
186.2		76
Os
190.2		77
Ir
192.2		78
Pt
195.1		79
Au
197.0		80
Hg
200.6		 81
Tl
204.4		82
Pb
207.2		83
Bi
209.0		84
Po
(209)		85
At
(210)		86
Rn
(222)
87
Fr
(223)		88
Ra
226.0		 103
Lr
(260)		104
Rf
(261)		105
Db
(262)		106
Sg
(263)		107
Bh
(264)		108
Hs
(265)		109
Mt
(266)		110
Ds
(267)		111
Rg
(281)		112
Cn
(285)		 113
Uut
(286)		114
Fl
(289)		115
Uup
(289)		116
Lv
(293)		117
Uus
(294)		118
Uuo
(294)
57
La
138.9		58
Ce
140.1		59
Pr
140.9		60
Nd
144.2		61
Pm
(145)		62
Sm
150.4		63
Eu
152.0		64
Gd
157.3		65
Tb
158.9		66
Dy
162.5		67
Ho
164.9		68
Er
167.3		69
Tm
168.9		70
Yb
173.0
89
Ac
227.0		90
Th
232.0		91
Pa
231.0		92
U
238.0		93
Np
237.0		94
Pu
(244)		95
Am
(243)		96
Cm
(247)		97
Bk
(247)		98
Cf
(251)		99
Es
(252)		100
Fm
(257)		101
Md
(258)		102
No
(259)
Legend
Li Solid Br Liquid He Gas Tc Man Made
Alkali metals Alkali earth metals Transition metals Inner transition metals
Other metals Noble gases Halogens Other nonmetals

Li, Na, and K in water

In this video the lithium, Li, is on the right, the sodium, Na, is on top, and the potassium, K, is on the left.

Homework

See class homework in Canvas for Day 16.