CHEMISTRY UNIT 2 THE STRUCTURE OF THE ATOM AND THE PERIODIC TABLE.
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CHEMISTRY UNIT 2 THE STR UCT URE OF THE ATO M A ND THE PERI ODI C TA BLE
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Transcript of CHEMISTRY UNIT 2 THE STRUCTURE OF THE ATOM AND THE PERIODIC TABLE.
CHEMISTR
Y UNIT
2THE S
TRUCTURE OF
THE ATOM
AND T
HE
PERIODIC
TABLE
STRUCTU
RE OF
THE A
TOM
ST
RU
CT
UR
E O
F TH
E A
TO
M
ST
RU
CT
UR
E &
AR
RA
NG
EM
EN
T O
F PE
RI O
DI C
T AB
L E
TR
EN
DS
AN
D P
AT T
ER
NS
ON
PE
RI O
DI C
TA
BL E
Nucleus Center of an atom Made up of:
Protons Positive charge
Neutrons Neutral charge
Electron Cloud Surrounds the nucleus Made up of:
Electrons Negative charge
THE STRUCTURE OF AN ATOM - TWO PARTS
Atom
NucleusCenter of
atom
Proton
Positive Charge
Neutron
Neutral Charge
Electron CloudSurrounds the
nucleus
Electron
Negative Charge
Positively charged
Atoms of the same element have the same number of protons.
atomic number
No two elements have the same atomic number.
Change # of protons? Different element
PROTONS
CHECK YOUR UNDERSTANDING
Element
Atomic
Number
Protons (p+)
1
Platinum
16
Fluorine
79
Calcium
Neutrally charged
Atoms of the same element may have different number of neutrons.
Mass Number Neutrons + Protons
Change # of neutrons?
Different isotope
NEUTRONS
Hydrogen
Most naturally occurring isotopes are stable
A few naturally occurring isotopes and all man-made isotopes are unstable
Unstable isotopes can become stable by releasing different types of particles.
Radioactive Decay
ISOTOPES
CHECK YOUR UNDERSTANDING
URANIUM
Mass Number 235
Atomic Number
Number of Neutrons 143
URANIUM
Mass Number 238
Atomic Number
Number of Neutrons
Negatively charged
Atoms of the same element may have different numbers of electrons
Atoms neutral unless stated otherwise
Charge
Change # of Electrons?
Ion
ELECTRONS
Electrons have energy kinetic Level
How Many Electrons Fit in the
Level
1 2
2 8
3 18
4 32
ELECTRON CLOUD
CHECK YOUR UNDERSTANDING
Atom/Ion Symbol
Atomic Number Protons Charge Electrons
17
I
12 10
19 +1
56 54
-1 36
8 -2
-3 18
ISOTOPE NOTATION
How many protons?
How many neutrons?
How many electrons?
CHECK YOUR UNDERSTANDING
REVIEW
Atom
NucleusCenter of
atom
Proton
Positive Charge
Change? New atom
Neutron
Neutral Charge
Change? New isotope
Electron CloudSurrounds the
nucleus
Electron
Negative Charge
Change? New ion
STRUCTU
RE &
ARRANGEMENT OF
THE P
ERIODIC
TABLE
ST
RU
CT
UR
E O
F TH
E A
TO
M
ST
RU
CT
UR
E &
AR
RA
NG
EM
EN
T O
F PE
RI O
DI C
T AB
L E
TR
EN
DS
AN
D P
AT
TE
RN
S O
N P
ER
I OD
I C T
AB
L E
INFORMATION IN THE PERIODIC TABLE
Name of the Element
Symbol for the Element
Atomic Number: Number of protons
All atoms on the periodic table are neutral
Atomic Mass: The average mass of the isotopes of an element Protons + Neutrons
SYMBOLS
One or two letters that represent an element
Calcium is Ca1. First letter is Capital2. 2nd (& 3rd) letter is Lower case3. All letters are PRINTED only
STRUCTURE AND ARRANGEMENT
M E N D E L E E V
Grouped elements with similar properties.
Left gaps for what he assumed were undiscovered elements.
Periodic Law: Elements exhibited a periodic
recurrence of properties when arranged in order of increasing atomic mass.
C U R R E N T LY
Elements are arranged by increasing atomic number
Rows (Periods) Column (Groups) Families
Except Hydrogen
Better placed in group 7A. Some books place it
in both
ELEMENTS IN SAME GROUP SHARE SIMILAR PROPERTIES
TRENDS A
ND
PATT
ERNS ON T
HE
PERIO
DIC TA
BLE
ST
RU
CT
UR
E O
F TH
E A
TO
M
I NF O
RM
AT
I ON
GI V
EN
BY
TH
E P
ER
I OD
I C T
AB
L E
TR
EN
DS
AN
D P
AT T
ER
NS
ON
PE
RI O
DI C
TA
BL E
Roughly 80% of all elements
Located left of the stair-step line
All metals have similar properties
Good conductors Reactive Usually make positive
ions Easily combined to make
alloys
METALS
Located right of the stair-step line
All non-metals have similar propertiesGenerally poor conductors of heat and electricityAre good oxidizing agents (like rust)Form negative ionsSolid, liquid or gas at room temperature
NON-METALS
Touch the stair-step line
All properties between metals and non-metals
Often good Semi-conductors Electrical
conductivity between conductors (such as copper) and insulators (such as glass).
METALLOIDS
ELECTRONEGATIVITY
An atom’s ability to attract electrons to itself
increases across periodsdecreases down groups
Size of an atomDecreases across periods Increases down groups
ATOMIC RADIUS
Similar properties in Groups/Families
PROPERTIES
Group 1 (except H)
All are shiny, soft metals
Highly reactive
ALKALI METALS
Group 2Highly reactive-
not as reactive as alkali
Very high melting point
Distinguishable by flame color
ALKALINE EARTH METALS
Group 17 Name means “salt formers” React with metals
to form saltsHighly reactive
HALOGENS
Group 18Stable/non-reactive
ColorlessOdorless
NOBLE/INERT GASSES
Group 3-12Very hardHigh melting/boiling points
High conductivity
TRANSITION METALS
Periods 6-7 Elements 57-71 and 89-103
Removed form main body of the table so it fits on a standard page
Actinides are all radioactive
Lanthanides bond with water
LANTHANIDE AND ACTINIDE SERIES
Group 13 is the Boron family
Group 14 is the Carbon family
Group 15 is the Nitrogen family
Group 16 is the Oxygen family
OTHER GROUPS
