philosopher who believed that: there are 4 elements: earth, water, air, fire. matter is divisible

Introduction to Chemistry

Aristotle (Greece, 4th Century BC)

Philosopher who believed that:

There are 4 elements:earth, water, air, fire.

Matter is divisible.

Democritus (Greece, 4th Century BC)

First atomic theory

Atom (indivisible).

Alchemists (~300BC-1650 AD)China, India, Arabia, Europe, Egypt

• Aiming to:Change common

metals to gold.Develop medicines.

• Developed lab equipment.

• Mystical.

Galileo Galilei (Italy 1564 AD)

Father of the scientific method (along with the Englishman Francis Bacon 1500’s).

Antoine Lavoisier (France 1743-1794)

Regarded as the Father of Chemistry. Designed equipment. Used observations and measurements. Discovered nitrogen.

Dmitri Mendeléev (Russia, 1834-1907)

First Periodic Table of elements.

Pure substances that cannot be separated into different substances by ordinary processes

Are the building blocks of matter112 elements known today

Examples: carbongoldcalcium

LecturePLUS Timberlake 8

Elements

Use 1 or 2 letter abbreviations Capitalize the first letter only

Examples:C carbon Co cobaltN nitrogen Ca calciumF fluorine Br bromine

O oxygen Mg magnesium


Symbols of Elements

Element Symbol Latin name

Copper Cu cuprumGold Au aurumLead Pb plumbumMercury Hg

hydrargyrumPotassiumK kaliumSilver Ag argentumSodium Na natriumTin Sn stannumLecturePLUS Timberlake 10

Symbols from Latin Names

O 65.0 % K 0.34C 18.0 S 0.26H 10.0 Na 0.14N 3.0 Cl 0.14Ca 1.4 Fe 0.004P 1.0 Zn 0.003 Mg 0.50Trace ElementsAs, Cr, Co, Cu, F, I, Mn, Mo, Ni, Se, Si, V


% Major Elements in the Body

Select the correct symbol for each:A. Calcium

1) C 2) Ca 3) CA

B. Sulfur 1) S 2) Sl 3) Su

C. Iron1) Ir 2) FE 3) Fe


Learning Check

Select the correct symbol for each:A. Calcium

2) Ca

B. Sulfur 1) S

C. Iron3) Fe


Solution

Select the correct name for each:A. N

1) neon2) nitrogen 3) nickelB. P

1) potassium 2) phogiston 3) phosphorus

C. Ag1) silver 2) agean 3)

gold


Learning Check

Select the correct name for each:A. N

2) nitrogen B. P

3) phosphorusC. Ag

1) silver


Solution

The periodic table is an arrangement of the elements according to similarities in their chemical and physical properties.


Periodic Table

The characteristics of a substance that can be observed without changing the substance.

Color Size Shape Density Freezing and Boiling Points Odor


Physical Properties

Periodic Table

Using the Periodic Table

Atomic Number– Equal to # protons = # electrons– Periodic Table is arranged by this number

Symbol – “Shorthand” for the element – Note 2nd

letter is always lowercase

Atomic Mass Number

– Total AVERAGE mass of Protons + Neutrons + Electrons

17

Cl

35.5

Electron Energy Levels Electrons are arranged in “Shells” around nucleus

in predictable locations Fill “seats” closest to nucleus first (concert – best

seats) “Seats” available

◦ Shell #1 2 electrons◦ Shell #2 8 electrons◦ Shell #3 8 electrons◦ Shell #4 18 electrons◦ Shell #5 32 electrons◦ Shell #6 50 electrons

Ex. Carbon has 6 total electrons so…

Two electrons on first energy level

Four electrons on second energy level

Question: Could we fit more electrons on the second energy level if there were more electrons in carbon??

Atomic Structure

17

Cl

35.5

Total Mass of Nucleus36 - 17 = 18 neutrons

Element NameChlorine

Total # of protons and electrons (in a neutral atom)17 protons in nucleus17 electrons orbiting nucleus

Notice: electrons follow energy level rules from previous slide.

(Round Atomic Mass)

Vertical columns on the periodic

tableSimilar physical propertiesSimilar chemical properties


Groups of Elements

1 2 3 4 5 6 7 8


Groups on the Periodic Table

Group 1 Alkali Metals

Group 2 Alkaline Earth Metals

Group 7 Halogens

Group 8 Noble Gases


Representative Groups

1 2 3 4 5 6 7 8


Location of Some Groups

Al mk ea tl ai l s

Alkaline

Halogens

I Gn ae sr et s

Horizontal rows from Group 1 to

Group 8.

Numbered 1, 2, 3, ….

Include representative elements and

transition elements


Periods on the Periodic Table

123456


Periods on the Periodic Table

philosopher who believed that: there are 4 elements: earth, water, air, fire. matter is divisible

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