Atoms that interact to form compounds are said to be chemically bonded

Atoms that interact to form compounds are said to be chemically bonded.

Whether atoms interactdepends almost entirelyon the arrangement oftheir outer energylevel (valence)electrons.

Only s and p sublevelelectrons are thoughtof as valence electrons.

The maximum numberof electrons, total, in thes and p sublevels is __

The maximum numberof electrons, total, in thes and p sublevels is 8.

Electrons in the d and fsublevels are NEVER in the outer energylevel of an atom.

Bonding - 7 min

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

Electrons are transferredbetween atoms.

One atom gains electronswhile another atomloses electrons.

When this happens, thecharges within each atomare no longer balanced...

the atoms have becomeions - one with a positivecharge, the other negative.

The force of attraction between these opposite charges hold the ions together in an ionic bond.

Ionization - the process of removing an electron froman atom to form an ion.

Ionization energy - the energy needed to removean electron from an atom.

Electron affinity - the tendency of an atom to attract electrons.

Electron affinity determines the

type of bond formed.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Metals generally havea low electron affinity.

Nonmetals generally havea high electron affinity.



Electrons are sharedbetween atoms.

Atoms with similarelectron affinities usuallyform covalent bonds.

Both atoms have an equal attraction for the electrons being shared.

The force of attraction between the nuclei and the shared electrons holds the atomstogether in a covalent bond.

Chemical bonds are almost never totally ionicor totally covalent.

Bond types are oftenexpressed as a percentage of each type of bond.

The closer two atoms are onthe table, the more covalenttheir bond.

COand

CO2

The farther apart two atoms are on the table, the more ionictheir bond.

NaCl

100%Ionic

FrF

100%Covalent

F2

ZnS

50% Each

The electrons in metals can be thought of as being property of all the atoms.

The positive nuclei aresurrounded by a "sea" of electrons.

These loosely-held electronsare responsible for metalsbeing good conductorsof electricity.

A special type of bondbetween a hydrogen atomin a covalent molecule...

and an unshared electronin a nearby molecule.

Since a hydrogen atom isso small, it can get veryclose to other atoms -

causing electrons in thoseatoms to be attracted to it.

This is especially important with small, polar moleculeslike water.



It makes water a VERYGOOD solvent - especially with otherpolar substances.



Hydrogen bonding isresponsible for water'svery high specific heatcapacity...



the ability to absorblarge amounts of heatwith little changein temperature...



and its relativelyhigh boiling point.



two atoms of the same element covalentlybonded together.

Seven elements exist in natureONLY as diatomic molecules.

Know the sevendiatomic molecules!!

Hydrogen - H2

Nitrogen - N2

Oxygen - O2

Fluorine - F2

Chlorine - Cl2

Bromine - Br2

Iodine - I2

Begin with #7

There are 6 herein the shape of a 7

And 1 more here

A group of covalentlybonded atoms that hasan overall charge.





This group of atomsacts like a single ionwhen combining to form compounds.



The charge on apolyatomic ion isequal to itsoxidation number.

Certain electron arrangements are more

stable than others.

The most stable atomshave a full outerenergy level.

Octet Rule - the maximumnumber of electrons in theouter energy level is 8.

Atoms will form compoundsto reach eight electrons intheir outer energy level.

Remember - hydrogen &helium, with only oneenergy level, can onlyhold 2 electrons.

Atoms with half-filled sublevels are somewhatstable.

A way ofdrawing thevalenceelectrons.

p

p

p s

The chemical symbolrepresents thecenter of animaginary rectangle.

p

p

p s

The symbol represents the atom's nucleus andall electrons,EXCEPT thevalence electrons.

p

p

p s

Each side of the imaginaryrectangle represents an orbital within a sublevel of theouter energy level

p

p

p s

Valence electrons ineach orbital are representedby dots.

p

p

p s

These arrows show the order in which electrons are added to thediagram - beginning with s.

p

p

p s

The electron dot diagram for sodium looks like this -with one electronin the s orbital.

Na

What would the electrondot diagram formagnesium look like?

What would the electrondot diagram formagnesium look like? Mg

What would the electrondot diagram forAluminumlook like?

What would the electrondot diagram forAluminumlook like? Al

What would the electrondot diagram forSiliconlook like?

Hint: Remember Hund's Rule

What would the electrondot diagram forSiliconlook like? Si

What would the electrondot diagram forPhosphoruslook like?

What would the electrondot diagram forPhosphoruslook like? P

What can you say aboutthe stability ofan atom ofphosphorus? P

An atom of phosphorusis somewhat stablebecause ofthe half-filledp sublevel.

P

What would the electrondot diagram forSulfurlook like?

What would the electrondot diagram forSulfurlook like? S

What would the electrondot diagram forChlorinelook like?

What would the electrondot diagram forChlorinelook like? Cl

What would the electrondot diagram forArgonlook like?

What would the electrondot diagram forArgonlook like? Ar

What can you say aboutthe stability ofan atom ofargon? Ar

An atom of argon isvery stable becauseits outer energylevel is full. Ar

What would the electrondot diagram forCopper look like?

What would the electrondot diagram forCopper look like? Cu

All transition metals have only two dots - Why?

Cu



Notice the number ofdots is the same asthe group number.



Also notice that thesedots are not placedexactly as we discussed.



Many college chem booksstress symmetry of dotsmore than sublevels.



Since THIS class stressesthe periodic table,sublevels are important.

What do you think of?

OH

H

Can these 3 atom diagrams

OH

H be combined into1 molecule diagram?

AWater

MoleculeH2O

OH

HAll atoms have a filled

outer energy level.

This diagram not only showsproperly filledenergy levels,it correctlyshows the shape of a water molecule!!

OH

H

When 10 cm3 of acetone, C3H6O, are added to 10 cm3 of distilled water, the combined volume is NOT 20 cm3.

Hypothesis:

Chemical BondingTest Tomorrow

Whether atoms interactdepends almost entirelyon the arrangement oftheir _____ electrons.

Only ___ and ___ sublevelelectrons can be valence electrons.

_____ bonds occur whenelectrons are transferredbetween atoms.

When atoms gain orloose electrons, theybecome ____.

The tendency of an atom to attract electronsis called ____.

Atoms with similarelectron affinities usuallyform ____ bonds.

Bonding is usuallyexpressed as a ___ of each type of bond.

There are ___diatomic molecules.

Diatomic molecules mustbe written with asubscript of ___.

A group of covalentlybonded atoms withan overall charge iscalled a ___.

In an electron dot diagram,dots represent ___.

The ___ states thatthe maximum number of electrons in theouter energy level is 8.

The valence electrons inthe atoms of a sample ofmetal belong to ___.

The oxidation number ofa polyatomic ion isequal to its ___.

Which of these atoms ismost likely to form anionic bond with sulfur?

Lithium, nitrogen, aluminum

Which of these atoms hasthe highest electron affinity?

Lithium, sodium, carbon

Which of these atoms willform a negative ion?

iron, tin, chlorine

How many dots are in theelectron dot diagram of arsenic?

How many dots are in theelectron dot diagram of mercury?

Which of these atoms is the most stable?

iron, nitrogen, chlorine

How many of these atoms do not conform to the octet rule?

hydrogen, helium, argon

The formula for thephosphate ion is ___.

The formula for theammonium ion is ___.

The formula for thesulfate ion is ___.

Chemical Bonding

Documents

Atoms that interact to form compounds are said to be chemically bonded