The Periodic Table

The Periodic TableElements

Periodic Table of Elements

Part I: PTDiscovery of Elements

• Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth.

• Scientists have identified 90 naturally occurring elements, and created about 28 others(synthetic).

The most abundant element in the earth’s crust is oxygen.

Periodic LawElements( in periodic table) are arranged by increasing atomic #, they display a regular and repeating pattern of chemical & physical properties.

Dmitri Mendeleev Father of The Periodic Table

HOW HIS WORKED…

• Put elements in rows by increasing atomic weight.

• Put elements in columns by the way they reacted.

SOME PROBLEMS…• He left blank spaces for

what he said were undiscovered elements. (Turned out he was right!)

• He broke the pattern of increasing atomic weight to keep similar reacting elements together.

The Current Periodic TableMendeleev wasn’t too far off.Now the elements are put in rows by increasing

ATOMIC NUMBER!!The horizontal rows are called periods and are labeled from 1 to 7.The vertical columns are called (families) groups are labeled from 1 to 18.

Families (Groups) • Columns of elements are called

groups or families. • Elements in each family have

similar but not identical properties.

• All elements in a family have the same number of valence electrons.

Periods• Each horizontal row of elements is called a

period.• The elements in a period are not alike in

properties.• The properties change greatly across a

given row.• The first element in a period is always an

extremely active solid. The last element in a period, is always an inactive gas.

Vocabulary used to explain metals.Malleable = can be pounded into thin sheets

Ductile = can be drawn out into a thin wire

Lustrous: Shiny Brittle: hard but easy to break.

Hydrogen • Hydrogen belongs to a family of its own.

• diatomic ( H2,)• reactive gas.• Hydrogen was involved in the

explosion of the Hindenberg.• Hydrogen is promising as an

alternative fuel source for automobiles

• Hydrogen bomb

Alkali Metals

• 1st column on the periodic table (Group 1) not including hydrogen.

• Most reactive metals, always combined with something else in nature (like in salt).

• Soft enough to cut with a butter knife

• They react violently with water.

Alkali Earth Metals• Second column on the

periodic table. (Group 2)• Reactive metals that are

always combined with nonmetals in nature.

• Several of these elements are important mineral nutrients(such as Mg and Ca)

Transition Metals

• Elements in groups 3-12• Less reactive harder metals• Includes metals used in

jewelry and construction.

Other Metals● Solid.● Ductile &

malleable.● Conductors of

electricity & heat.

● Have relatively high density.

● Opaque.

Metalloids “The Ladder”

Properties between metals and nonmetals

Able to lose or gain electronsEx: Si appears lustrous, is brittle, not malleable or ductile. Poor conductor of heat and electricity than metals.

Useful in the semiconductor industry.

Halogens• Elements in group 17

Very reactive, volatile, diatomic, nonmetals

• Always found combined with other element in nature .

• Used as disinfectants and to strengthen teeth.

The Noble Gases

• Elements in group 18• VERY unreactive,

monatomic gases• Used in lighted

“neon” signs• Used in blimps to fix

the Hindenburg problem.

• Have a full valence shell.

Lanthanide and Actinide series.• The ~30 rare earth

elements are composed of the lanthanide and actinide series.

• One element of the lanthanide & most actinide are called trans-uranium, which means synthetic or man-made.

Diatoms are Twins!!!!

There are 7 Diatoms(Pairs)● Diatomic elements: In pairs by

nature. TWINS!!!(HOClBrIFN = Huckleberry Finn!)

▪ H2(g) N2(g) O2(g) F2(g) Cl2(g) Br2(l) I2(l)

▪ (volatile in liquid form - evaporates readily)

What does it mean to be reactive?Ex:

Charged AtomsCATION:(+)Positively charged atom.ANION:(-)Negatively charged atom.

What does it mean to be reactive?OCTET & DUET RULE

– All atoms (except hydrogen) want to have 8 electrons in their very outermost energy level (OCTET RULE.)

– Hydrogen want to have 2 electrons in its outermost energy level( DUET RULE)

– Atoms bond until this energy level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 5, 6, 7, valence electrons gain electrons during bonding.

Part II: Periodic Trends

Periodic trends, shows arrangement & provide quick prediction an element's property.

Major periodic trends include:• Atomic Radius• Electronegativity, • Ionization energy, • Electron affinity,

Atomic Radii(Radius)Atomic SizeIncrease

down group

Decrease across period

DECREASE

INCREASE

ElectronegativityType of MeasureAbility of an atom

to attract electrons– Dec. down

group (electron shielding)

– Inc. across period

Ionization Energy

Amount of energy needed to remove an electron– Inc. across

period– Dec. down group

(electron shielding)

Electron Affinity Amount of energy released when an electron is added to a neutral atom.

Is density a trend for Elements of PT?

Mini lab: Viewing Density as a Periodic TrendGo to one of the stations 5-7 & finish lab. Graph and answer the questions.

Periodic Trends Review1. Rank the following elements by increasing atomic radius:

C, Al, O, K.2. Rank the following elements by increasing electronegativity: S, O,

Ne, Al.3. What is the difference between electron affinity and ionization

energy?

4. Why does fluorine have a higher ionization energy than iodine? 5. Why do elements in the same family generally have similar

properties?

O, C, Al, K

Al, S,O,Ne

EA. Ability to attract electrons and I.E.energy to remove an electron.

Fluorine is located above the Iodine in the column.

They have the number of valence electrons in their outermost shell.

Matter(Additional notes on matter)• All matter is composed of atoms(elements) and

groups of atoms bonded together, called molecules.– Substances that are made from one type of atom only are

called pure substances. Can not be separated chemically or physically.

– Substances that are made from more than one or more than one type of atom bonded together are called compounds. Can be separated by chemical means only.

– Compounds that are combined physically, but not chemically, are called mixtures. Can be separated.

– Mixtures can be homogeneous(uniformed) or heterogeneous(not uniformed)

Elements, Compounds, Mixtures

• Sodium(Na+) an element.• Chlorine (Cl-) is an element.• When sodium and chlorine bond they make the

compound sodium chloride(NaCl), commonly known as table salt.

Salt is a compound.

Ocean is a mixture