Atomic StructureWhat is an Atom?

INB Page 123 • Add the Periodic Table of Elements!!

1.Hydrogen

2.Sulfur

3.Fluorine

4.Helium

5.Silicon

6.Boron

7.Carbon

8.Nitrogen

9.Sodium

10.Calcium

Use your Periodic Table to find the symbol for each element below (INB page 124) :

The answers are …

1.Hydrogen

2.Sulfur

3.Fluorine

4.Helium

5.Silicon

6.Boron

7.Carbon

8.Nitrogen

9.Sodium

10.Calcium

H

S

F

He

Si

B

C

N

Na

Ca

What is an Element?• Matter that is composed of one type of

ATOM

• Elements are abbreviated in scientific shorthand – either a letter or a pair of letters called a symbol. – Examples: Aluminum – Al, Oxygen – OBrain pop - Atoms

What is an atom?• The basic unit of matter!

•Smallest piece of matter that still has the properties of an element

•Atoms make up everything around you!• 92 Naturally occurring atoms • Scientists have created about 25 more

Atoms BrainPOP

What do atoms consist of?• Atoms consist of subatomic particles

– The nucleus• Protons• Neutrons

– The Electron Cloud • Electrons

The Nucleus• The nucleus is the center of the atom.

• The nucleus is made up of protons and neutrons.

• The nucleus contains MOST of the atom’s mass

Protons• Subatomic particle with a positive charge +.• All protons are identical, regardless of the element

in which they are found.• A proton has a mass of 1 amu (To get an idea of how

small an amu is, imagine the number 6 followed by 23 zeros. That is how many protons it would take to equal a mass of just one gram.)

• Determines the element (1 P = H, 8 P = O)

Neutrons• Neutrons are electrically neutral (have no charge).

• Like protons, all neutrons are identical.

• A neutron has slightly more mass than a proton, but the mass of a neutron is still considered to be 1 amu.

What is a Quark?• Quarks are believed to be one of the basic building

blocks of matter. Quarks were first discovered in experiments done at the Stanford Linear Accelerator Center in the late 1960's and early 1970's.

• Up and Down quarks, join together to form PROTONS and NEUTRONS.

Atomic Number• The number of protons in the nucleus of an atom

is the atomic number.• The atomic number identifies the element.• All hydrogen atoms – and only hydrogen atoms

– have 1 proton and an atomic number of 1.• Carbon atoms have 6 protons and an atomic

number of 6.• How many protons does oxygen, atomic # 8

have? Uranium, atomic number 92? Nitrogen, atomic number 7?

Electrons• Electrons have a negative charge.• Electrons have a mass of 1/1836 amu.

• What is an ION?– An Ion is an Atom or Molecule that has a

Different Number of Electrons than Protons• Adding Electrons Creates a NEGATIVE ion• Subtracting Electrons Creates a POSITIVE ion

BrainPOP - IONS

Electron CloudBlurry Area Containing

Electron

Nucleus

Protons + Neutrons