Atoms and the Periodic Table

Chapter 17

Mrs. Gerlach 10-11

Objectives 17-1 Define and describe protons, neutrons and electrons.

(Mass, location, charge) 17-2 Draw a Bohr model showing the correct number and

placement of electrons. 17-3 Know where to find atomic number and average

atomic mass for an element on a periodic table. 17-4 Calculate the number of protons, neutrons and

electrons for an element. 17-5 Calculate the number of atoms of each element in a

chemical compound. 17-6 Differentiate between atoms and isotopes. 17-7 Identify the subatomic particle that determines the

identity of the element.

Structure of the Atom

Section 1

Read the story about Atoms Family

We will fill in the info when you are done.

Jump to notebook

Structure

ParticleRelative

MassCharge Location

Proton 1 amu +1 nucleus

Neutron 1 amu 0 nucleus

Electron 0 -1Electron

cloud

REVIEW ATOMS FAMILY NOTES!!!

Periodic Table Key

28

NiNickel

58.69

Atomic Number- Tells us the number of protons and electrons the element has

Symbol

Element’s Name

Atomic mass- subtract atomic number from the atomic mass to get the number of neutrons the element has

Practice

19

KPotassium

39.0983

Number of Protons?

Number of Electrons?

Number of Protons?

Symbol?

Atomic Mass?

Models of Atom

p+

n0

History of the Atomic Model

In 1913 Niels Bohr proposed a model of the atom where electrons moved in definite orbits around the nucleus.

Bohr’s Model

Atoms on the PTAtomic number

Atomic mass

Drawing an Atomic ModelSTEP 1# of protons

• Equal to atomic #

STEP 2# of neutrons

• Equal to:atomic mass (rounded) - atomic #

Drawing an Atomic ModelSTEP 3# of electrons

• Equal to # of protons 1st energy level holds 2 e- 2nd energy level holds 8 e- 3rd energy level holds 18 e- 4th energy level holds 32 e-

Bohr Model Practice - Lithium

Bohr Model Practice - Sodium

Masses of AtomsSection 2

IsotopesDEF: Atoms of the same element

have different number of neutrons but the same number of protons and electrons.

Have different massesDifference due to number of

neutrons

•Showing IsotopesElement name – mass number

Hydrogen – 1

Hydrogen – 2

Mass NumberDEF: Sum of protons and

neutrons in the nucleus of an isotope

Different mass number for each isotope.

Based on the Atomic MassRound to a whole number

Counting AtomsSection 2

Objectives17-5 Calculate the number of

atoms of each element in a chemical compound.

Compounds have formulas.

H2O Subscript

•Applies to the element its attached to•May use parenthesis

Compounds have formulas.

7H2O Coefficient

•Applies to the FULL formula

CO2How many Carbon atoms are

present? How many Oxygen atoms?

3SO4How many Oxygen atoms? How many Sulfur atoms?

Practice!

S(H20)2

S = __ H = __ O = __

Practice!

12H2SO4

S = __ H = __ O = __

Practice!

8Na2(OH4)6

Na = __ H = __ O = __

Practice!

10C6H12O6(OH)12

C = __ H = __ O = __

3(Mg,Fe)7Si8

Mg = __ Fe = __ Si = __

Periodic Acid – 12H5IO6

I = __ H = __ O = __

THE END!