# Atoms and the Periodic Table - PowerPoint PPT Presentation

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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.

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Atoms and the Periodic Table

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## 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

• We will fill in the info when you are done.

## REVIEW ATOMS FAMILY NOTES!!!

### Periodic Table Key

Atomic Number- Tells us the number of protons and electronsthe 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

• Number of Protons?

• Number of Electrons?

• Number of Protons?

• Symbol?

• Atomic Mass?

p+

n0

### History of the Atomic Model

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

### Atoms on the PT

• Atomic number

• Atomic mass

### Drawing an Atomic Model

STEP 1

# of protons

• Equal to atomic #

STEP 2

# of neutrons

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

### Drawing an Atomic Model

STEP 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-

## Masses of Atoms

Section 2

VARIATIONS

of an element!

### Isotopes

• DEF: Atoms of the same element have different number of neutrons but the same number of protons and electrons.

• Have different masses

• Difference due to number of neutrons

### Showing Isotopes

• Element name – mass number

• Hydrogen – 1

• Hydrogen – 2

### Mass Number

• DEF: Sum of protons and neutrons in the nucleus of an isotope

• Different mass number for each isotope.

• Based on the Atomic Mass

• Round to a whole number

## Counting Atoms

Section 2

### Objectives

• 17-5 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

CO2

• How many Carbon atoms are present?

• How many Oxygen atoms?

3SO4

• How many Oxygen atoms?

• How many Sulfur atoms?

• S(H20)2

• S = __

• H = __

• O = __

• 12H2SO4

• S = __

• H = __

• O = __

• 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 = __