New Area of Focus: Periodic Table of the Elements. New Area of Focus: Periodic Table of the...

New Area of Focus: Periodic Table of the Elements.

Copyright © 2010 Ryan P. Murphy

The Periodic Table of the Elements is a…----


A chart of all the known elements.


Is in order of increasing atomic number and mass.


H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti Ga Ge As Se Br Kr

Atomic Mass and Atomic Number increases as you move across and down.


The table puts elements into groups with similar characteristics.


Allows us to recognize trends over the whole array of elements.


• All of the elements in a period have the same number of atomic orbitals.


IncreaseIn Energy

Please add to the sideEn

erg

y I

ncre

ases

Horizontal row is called a Period. (Same # of electron orbitals)

Vertical column is called a group/family. (Same # of valence electrons)


AMU increases from left to right and top to bottom.


Density of elements increase down a group

H He

Li Be B C N O F Ne



AMU increases as you go from left to right, and from top to bottom


Electronegativity increases from lower left to upper right.


Moving top to bottom down the periodic table, electronegativity decreases.

H He

Li Be B C N O F Ne



Electron negativ

ity


• The most strongly electronegative element, Fluorine (F).

• The least electronegative element is Francium (Fr).


“I want to give away

one electron.”

“I want to gain one electron”

“You guys should get together.”

Electronegativity - chemical property that describes the tendency of an atom to attract electrons towards itself.affected by both its atomic number and the

distance at which its valence electrons reside from the charged nucleus.


– Electrons with low ionization energies have a low electronegativity because their nuclei do not exert a strong attractive force on electrons.

– Elements with high ionization energies have a high electronegativity due to the strong pull exerted on electrons by the nucleus.


and Ions)Ionization energy is the energy required to remove an electron. (Gases and Ions)

Increasing Ionization Energies

The ionization energy (IE) is defined as the amount of energy required to remove electron from the outer shell

- increase as one moves from left to right within a given row (period) due to more electrons being added

- decrease as one moves down a column (group) because the outer electron shell is getting further away from the nucleus

https://en.wikipedia.org/wiki/Electron

As atoms get smaller, the valence electrons are closer to the nucleus so the attractive force holding the electrons is stronger and makes it harder to remove

New Area of Focus: Electron Orbitals


Valence electrons: Electrons in the outer most shell.


1 2 1 4 5 1

Total Electrons

Lewis Dot Structure- atom model that represents the valence electrons only.

- the valence electrons of atoms are the electrons that interact during the formation of compounds

En

erg

y I

ncre

ases

Drawing the Lewis Dot Structure for the first three rows.


1 2 3 4 5 67 8

Ion- an atom that has lost or gained electrons

- if losing electrons, the ion becomes more positive; ex. If it loses 2 electrons, it will have a +2 charge

- if gaining electrons, then the ion becomes more negative; ex. If it gains 2 electrons, it will have a -2 charge

En

erg

y I

ncre

ases

+1 +2 0-1-2-3

+/- 4

+3Charges +2

or more

Transition Metals are found in the middle.


Transition Metals are…-----


Malleable: To be shaped / made into sheets.



Ductile: Made into wire.

Good conductors of electricity.


• Copper (Cu) is a good conductor of electricity. – It is malleable and ductile.


Have a high luster (shine).


LUSTER

Conducts heat well.


Most have a high density.


Most are solid.Hg (mercury is a liquid metal)


Metallically bonded.


Many metals are reactive to chemicals.


Almost 75% of all elements are classified as metals.


Alloys: Metals are easily combined


• Bronze age: Copper and tin


• Continued Metals…


• Some of the metals. Use your table….– Actinide Metals, Lanthanide Metals, Alkali Metals,

Alkaline-Earth Metals, Noble Metals, Rare Metals, Rare-Earth Metals, and Transition Metals


• Flame test– Can be used to visually determine the identity

of an unknown metal or metalloid ion based on the characteristic color when burned.

– The heat of the flame converts the metal ions into atoms which become excited and emit visible light.

– The characteristic emission spectra can be used to differentiate between some elements.• Learn more at…• http://www.chem.purdue.edu/bcce/Scaling_a_flashy

_demonstration.pdf

http://www.chem.purdue.edu/bcce/Scaling_a_flashy_demonstration.pdf

http://www.chem.purdue.edu/bcce/Scaling_a_flashy_demonstration.pdf

Metalloids / Semi metals: Properties of metals and non-metals---


Semi-conductors


Brittle


Can have luster.


H He

Li Be B C N O F Ne



Key: Metalloids / Semimetals


Non-MetalsNot metals


H He

Li Be B C N O F Ne



Key: Non-metals


H

Non-metals…-----


H and He are non-metals.


They are poor conductors.


Which is a conductor and which is a insulator?

ABInsulator

Conductor

They are brittle (break when hit).


Dull in color. (No Luster)


Poor conductors of heat.


They may be transparent or translucent.


They exist as a… (s), (l), (g).


Solid Liquid Gas

SSulfur Br

Bromine

ClChlorine

Covalently bonded.


CH4 Methane Electron Negativity Diff.Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

Differences 1.7 or greater, the bond is usually ionic, Differences Less than 1.7, the bond is usually covalent,

Unless the difference is less than 0.5 the bond has some degree of polarity Differences of less than 0.5 are considered to be nonpolar.

Nonpolar Covalent

Bond

They have a low density.


Low or High?

New Area of Focus: Periodic Table of the Elements. New Area of Focus: Periodic Table of the...

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