Today’s Objectives: By the end of today, you should be able to do the following: 1.Define nucleus 2.Recall the parts of an atom 3.Be able to determine.

Today’s Objectives:By the end of today, you should be able

to do the following:1.Define nucleus2.Recall the parts of an atom3.Be able to determine the atomic number and atomic mass of an atom4.Be able to calculate the number of protons, electrons, and neutrons in an atom

Shelf Shelf

Door

Cashier

Example Store: (you will have two shelves, refrigerator and freezer)

Focus Assignment:Identify all that you know about these

elements from the periodic table in your book:

1.Helium2.Lithium3.Boron4.Sulfur

5.Chlorine

Recall: Atomic Number, Group, Period etc.

Do Now – Write a paragraph about what you see. Note what items are in each isle. Note the expressions on the peoples face.

How does this compare to your local grocery store?

3.1 – Atomic Structure1. Atomic Structure

2. The nucleus

4. Particle Charges

3. Electrons

5. Atomic Number

7. Number of Neutrons

6. Atomic Mass

Atomic Structure

E

1. Atomic Structure

Made of protons, electrons and neutrons

P

P

N

N

E

Protons

Neutron

Electrons(2 electrons here)

2. The nucleus Made of protons and neutrons bound tightly together

E

P

P

N

N

E

Nucleus

3. Electron location

Electrons float around the nucleus in “clouds of probability”

Electron probability clouds: More on this later

4. Particle Charges

Proton = +1Neutron = 0 Electron = -1

E-1

P+1N0

N0

E-1

P+1

Therefore, in a neutrally charged atom,

the # of electrons = # of protons

Atomic Number and Mass

5. Atomic Number

Number of protons in an atom (smaller number of the periodic table)

2

He4.003

Helium

Atomic Number

QUESTION: How many

protons does helium have?

= 2p+

5. Atomic Number

Number of protons in an atom (smaller number of the periodic table)

3

Li6.941

Lithium

Atomic Number

QUESTION: How many

protons does lithium have?

= 3p+

5. Atomic Number

Number of protons in an atom (smaller number of the periodic table)

32.453

S16

Sulfur

Atomic Number

QUESTION: How many

protons does sulfur have?

= 16p+

6. Atomic Mass Amount of protons and neutrons in an atom - average of isotopes (larger number on the periodic table)

2

He4.003

Helium

QUESTION: What is the atomic mass of Helium?

= 4.003

6. Atomic Mass Amount of protons and neutrons in an atom (larger number on the periodic table)

6.941

Li3

Lithium

QUESTION: What is the atomic mass of Helium?

= 6.941

7. Number of Neutrons

Atomic Mass – Atomic Number =

# of Neutrons

24Mg

1225Mg

1226Mg

1212 Protons12 Neutrons

12 Protons13 Neutrons

12 Protons14 Neutrons

7. Number of Neutrons

Atomic Mass – Atomic Number =

# of NeutronsIf no isotope is given, round for the atomic mass

2

He4.003

Helium4

Atomic Mass = 4Atomic # = 2

4 -2 2 n0

7. Number of Neutrons

Atomic Mass – Atomic Number =

# of NeutronsNote: We round for the atomic mass

3

Li6.941

Lithium7

Atomic Mass = 7Atomic # = 3

7 -3 4 n0

Questions?

3.1 – Atomic Structure1. Atomic Structure Made of protons, electrons and neutrons

(same amount of electrons and protons.)

2. The nucleus

4. Particle Charges

3. Electrons

5. Atomic Number

7. Number of Neutrons

6. Atomic Mass

Made of protons and neutrons bound tightly togetherFloat around the nucleus in clouds

Proton = +1, Neutron = 0, Electron = -1

Number of protons in an atom (top number of the periodic table)

Amount of protons and neutrons in an atom (bottom number on the periodic table)Atomic Mass – Atomic Number = # of Neutrons

E

1. Atomic Structure

Made of protons, electrons and neutrons

P

P N

E

P

N

NN

E E