ATOMIC Theory

The

What is the story ofthe ATOMS?

MATTER,the stuffaround us

is used to create ATOMS

ATOMSare used to create the

ELEMENTS

ELEMENTSare used to create the

MOLECULES

It just goes on..

But when we talk about the story of the atom..

ThisENTIREthing,really starts off with

THIS GUYcalled..

THE NUCLEUS

prot

on

prot

on

proton

proton

proton

neutron neutron

neutron

protonsositive charge

Neutronso charge

What is the net charge of this nucleus?

4

5

1

2

3

31

2

6

6 protons = +63 neutrons = 0but no

charge

= +6

The Electron Cloudelectron

electron

electron

electron

electron

electron

Electronsnegative charge

1

2

3

4

5

6

What is the net charge of the atom?

6 nucleus = + 66 electrons = - 6 = 0

Make sure you read the question well.

1. What is the net charge of the atom?that would be 0

2. What is the net charge of the nucleus?that’sgonna be be+6

terms

Understanding the diagram is veryimportant. Because we’re gonna getinto to the..COMMONLY

used

ATOMIC NUMBER-the number of protons in the nucleus

LOOKING AT THISATOM HERE:

What is the atomicnumber ?

6

MASS NUMBER-the number of protons plus the number of neutrons

LOOKING AT IT

6

atomicmass

Protons Neutrons

3+ = 9

Let’s shift into anotheraspect, when it comesdown to andATOMS

ELEMENTS

CHEMISTRYthere are ways in representingthe

THREEelements

in

* of the periodic table

CC – 8

X

6

12 . 0

6

14in the periodic table..

sometimes..

finally,in some

circumstances..

Let’s use the concepts we

looked at, a second ago.

8 – 6 = 2 neutrons

CC – 8

X

6

12 . 0

6

14

atomicnumber

massnumber

atomicnumber

massnumber

this is NOT themass number

C – 8 C – 12 C – 18

C – 20 C – 22 C – 24

Different forms of CARBON

ISOTOPES

same # of PROTONS but different # of NEUTRONS

same ATOMIC # but different MASS #

C – 8 C – 12 C – 18

C – 20 C – 22 C – 24

Different weights of CARBON

11 . 8 g 12 g 11 . 6 g

12 . 4 g 12 . 2 g 12 g

What is the AVERAGE WEIGHT of all these ISOTOPES of Carbon?

12 AND THISIS WHAT…

C6

12 . 0

…THIS NUMBERREPRESENTS

the ATOMIC WEIGHT- average weight of all the ISOTOPES for a given element

And it’s really, REALLYimportant not to confuse

that with the MASS number

IT MAKES SENSE

ATOMIC WEIGHT MASS NUMBER- has DECIMAL POINTbecause it representsan AVERAGE number

- has no DECIMAL POINT.either there are protons or neutrons or none,there's NO AVERAGEbeing taken.

KEEP ALL THAT IN MIND

Those THREE ways, in terms of how they represent things in

GENERALCHEMISTRY is

HUGE

THANK YOU