Biochemistry Chemistry of Life General Chemistry Elements: Substances that cannot be broken down...

Biochemistry

Chemistry of Life

General Chemistry

Elements: Substances that cannot be broken

down chemically into simpler substances.

Periodic Table of Elements

General Chemistry

Atoms: A particle that makes up an element. Still contains the same chemical

properties of that element.

Atomic Structure

6 electrons6 protons6 neutrons

Carbon 12

Electrons are part of whatmakes an atom an atom

Electrons are part of whatmakes an atom an atom

atom

But where exactly are theelectrons inside an atom?

Orbitalsare areas within atoms

where there is a high probablilityof finding electrons.

Knowing how electrons arearranged in an atom is

importantbecause that governshow atoms interact

with each other

Let’s say you have aroom with flies flyingaround in it

The flies are not justanywhere in the room.They are inside boxes inthe room.

You know where theboxes are, and youknow the flies areinside the boxes, but…

you don’t know exactlywhere the flies areinside the boxes

The room is an atomThe flies are electronsThe boxes are orbitals

The room is an atomThe marbles are electrons

The boxes are orbitals

Science has determined where theorbitals are inside an atom, but itis never known precisely where theelectrons are inside the orbitals

the billions of interactions of atomsconstantly going on around youdepend on how the electrons

are arranged in each atom

the billions of interactions of atomsconstantly going on around you

depend on how the electronsare arranged in each atom

the arrangement of an atom’s electrons(its orbitals)

govern how that atom will interactwith other atoms

the billions of interactions of atomsconstantly going on around you

depend on how the electronsare arranged in each atom

the arrangement of an atom’s electrons(its orbitals)

govern how that atom will interactwith other atoms

If atoms did not interact with each other,you would not be sitting here reading this

Isotopes

General Chemistry

Molecules: Two or more atoms of the same or

different elements. Covalently bonded.

H2 =

General Chemistry

Compounds: Two or more atoms of different

elements.. May have covalent bonds OR ionic

bonds.

H2O =NaCl =

+ -

In an IONIC bond,electrons are lost or gained,resulting in the formation of IONS

in ionic compounds.

FK

FK+ _

The compound potassium fluorideconsists of potassium (K+) ions

and fluoride (F-) ions

FK+ _

The ionic bond is the attractionbetween the positive K+ ion

and the negative F- ion

Ionic Bonding

Sowhatarecovalentbonds?

In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).

But rather than losing or gainingelectrons,atoms now share an electron pair.

In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).

But rather than losing or gainingelectrons,atoms now share an electron pair.

The shared electron pairis called a bonding pair

Cl2

Chlorineforms

acovalent

bondwithitself

ClClHowwilltwochlorineatomsreact?

ClClEach chlorine atom wants to gain one electron to achieve an octet

ClClNeither atom will give up an electron –chlorine is highly electronegative.

What’s the solution – what can theydo to achieve an octet?

Cl Cloctet

Cl Cl

circle the electrons foreach atom that completestheir octets

octet

Cl Cl


The octet is achieved byeach atom sharing theelectron pair in the middle

Cl Cl


This is the bonding pair

Cl Cl


It is a single bonding pair

Cl Cl


It is called a SINGLE BOND

Cl Cl


Single bonds are abbreviatedwith a dash

Cl Cl


This is the chlorine molecule,

Cl2

O2

Oxygen is also one of the diatomic molecules

How will two oxygen atoms bond?

OO

OOEach atom has two unpaired electrons

Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO

OOBoth electron pairs are shared.

6 valence electronsplus 2 shared electrons

= full octet

OO

two bonding pairs,

OOmaking a double bond

OO=For convenience, the double bond

can be shown as two dashes.

OO

OO=This is the oxygen molecule,

O2

this is so

cool!!

Covalent bonding allows for an amazingly large variety

of compounds such as

small compounds likewater and carbon dioxide,

and ethanol (alcohol),

to larger compoundssuch as aspirin,

(21 atoms)

and the sex hormones

estradiol(estrogen)

and

testosterone,

(49 atoms)

(44 atoms)

to all of the 40,000 proteinsyou have in your body,

including

insulin,with 779 atoms,

and hemoglobin,with about 11,000 atoms!

There are an estimated1040 possible compounds

containing up to 50 atoms

The known chemical world,including natural andsynthetic compounds,

is far far far below 1% of that.

NATURE volume 442 p. 502 3 August 2006

As of 2007, there are about31,000,000 known compounds;

CAS registry: http://www.cas.org/cgi-bin/regreport.pl

About 12.5 million of thoseare commercially available.

Thousands of new compoundsare discovered or synthesized

every week!

Covalent Bonding

Electrons are shared between the two atoms

Biochemistry Chemistry of Life General Chemistry Elements: Substances that cannot be broken down...

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