Do Now Dec 22

- Explain the difference between a proton, an electron and a neutron.

The Periodic Table Elements• Boxes in the periodic table contain a lot of

information. To understand this information, it is necessary to refer to the periodic table’s key

Atomic Number

Element Symbol (a capital letter or a capital followed by a lower case letter)

Atomic Mass

8

O

Oxygen

15.999

Element Name

Atomic Number• Atomic number- the number of protons in the nucleus of

an atom• Equal to the number of electrons to make an atom neutral

+++

--

-

What would be the atomic

number of this atom?

Atomic Mass• Atomic mass- the total number of protons and

neutrons in an atom’s nucleus• Expressed in Atomic Mass Units (amu)• Each proton or neutron has a mass of 1 amu

+++

-

-

-What would be the atomic mass of this

atom?+ 3

4

3 protons + 4 neutrons = an atomic mass of 7

amu

Why did we not account for the electrons when calculating

the atomic mass?

Atomic Mass• Atomic mass- the total number of protons and

neutrons in an atom’s nucleus• Expressed in Atomic Mass Units (amu)• Each proton or neutron has a mass of 1 amu

+++

-

-

-What would be the atomic mass of this

atom?+ 3

4

3 protons + 4 neutrons = an atomic mass of 7

amu

Why did we not account for the electrons when calculating

the atomic mass?

Sub-atomic ParticlesSize Comparison

(protons, neutrons, electrons, & quarks)

Size in atoms

Size in meters

(m)

Atom 1 10-10

Nucleus __1__10,000

10-14

Proton or

Neutron

___1___100,000

10-15

Electron or

Quark

_____1____100,000,00

0

10-18

(at largest)

+

++

+

+++

-

-

-

-

--

-

-+

Stations

• 1. Students will be able to calculate the atomic mass unit in order to determine atomic mass unit. Complete math section in textbook on page 93.

• 2. Students will be able to infer information about electromagnetic energy in order to answer questions based on information. PSSA LTS orange pages 76 to 79.