OCTOBER 8, 2013

Turn in your homework if you have it. Lab Sheet and Measuring Matter due tomorrow!!

Date your journal. Title: Atomic Structure

ATOMIC THEORY TIMELINE

SIGNIFICANT CONTRIBUTIONS

1803 1911 Rutherford Dalton

1904 JJ Thomson 1913 Bohr Plum pudding

NUCLEAR MODEL OF THE ATOM

A conceptual model of the atom in which a smallpositively-charged nucleus is surrounded byplanetary electrons

LOCATIONS IN THE ATOM

ATOM HAS TWO LOCATIONS:

1. NUCLEUS Small Center of the Atom Made of Protons and Neutrons Mass of the Atom Positively Charged

2. ELECTRON CLOUD- Surrounds the Nucleus- Mostly empty space

- Where electrons orbit the nucleus- The cloud is huge, the electrons are tiny- The electron cloud has areas where electrons are more likely to be found and areas where they are less likely to be found

PICTURE THIS…..

A football stadium, which represents the atomThe nucleus would be in the center on the 50

yd line, but the protons and neutrons that make up the nucleus would be about the size of sesame seeds. Almost all of the mass is here!!

The rest of the stadium would be the electron cloud, but the electrons would not be able to be seen if the atom were the size of a football stadium. Atoms are mostly empty space!!!!

PROTONS (+)

Positively charged particles

Help make up the nucleus of the atom

Help identify the atom (could be considered an atom’s DNA)

Equal to the atomic number of the atom

Contribute to the atomic mass

Equal to the number of electrons

+

+

+++

+++

-

-

-

-

--

-

-+

NEUTRONS

Neutral particles; have no electric charge

Help make up the nucleus of the atom

Contribute to the atomic mass

+

+++

+++

-

-

-

-

--

-

-+

ELECTRONS (-)

Negatively charged particles

Found outside the nucleus of the atom, in the electron orbits/levels (rings) 2 – 8 - 8

Move so rapidly around the nucleus that they create an electron cloud

Mass is insignificant when compared to protons and neutrons (mass is negligible)

Equal to the number of protons

Involved in the formation of chemical bonds

-

+

+++

+++

-

-

-

-

--

-

-+

SUBATOMIC PARTICLES

Particles that are smaller than the atomPROTONS (p+) in nucleusNEUTRONS (no ) in nucleusELECTRONS (e -) in electron cloud