Atomic Structure. What are the 3 major parts of an atom

Page
2

Slide 16

Describe Electron

Electrons are negatively charged particles that surround the atom's nucleus. Electrons were discovered by J. J. Thomson in 1897.

Electrons determine properties of the atom. Chemical reactions involve sharing or exchanging electrons.

Slide 17

Describe Nucleus

Slide 18

Describe Nucleus

The nucleus is the central part of an atom. It is composed of protons and neutrons.

The nucleus contains most of an atom's mass.

It was discovered by Ernest Rutherford in 1911.

Slide 19

Describe Quark

Slide 20

Describe Quark

Believed to be one of the basic building blocks of matter. Quarks were first discovered in experiments done in the late 1960's and early 1970's.

Three families of quarks are known to exist. Each family contains two quarks. The first family consists of Up and Down quarks, the quarks that join together to form protons and neutrons.

The second family consists of Strange and Charm quarks and only exist at high energies.

The third family consists of Top and Bottom quarks and only exist at very high energies.

Slide 21

Describe Isotope

Atoms that have the same number of protons but different numbers of neutrons

Slide 22

Describe Isotope

Example:

http://education.jlab.org/glossary/isotope.html

Slide 23

What is the Electron Cloud Model?

Slide 24

What is the Electron Cloud Model?

Model of the atom pictures the electrons moving around the nucleus in a region called an electron cloud.

The electron cloud is a cloud of varying density surrounding the nucleus. The varying density shows where an electron is more or less likely to be. Atoms with electrons in higher energy levels have additional electron clouds of different shapes that also show where those electrons are likely to be.

For more information, click here:

http://regentsprep.org/Regents/physics/phys05/catomodel/cloud.htm

Slide 25

What is the Electron Cloud Model? Diagram 1:

Slide 26