Intro to the Atomic TheoryElements, Atoms, and Subatomic Particles

Bill Nye - Atoms

Matter

What is matter? It is the substance that all objects are made up of

What is matter made up of? Atoms – these are the smallest particle of any element

Atoms

What are atoms made up of? Subatomic particles

What are subatomic particles? Particles that are smaller than the atom/ Parts that make up the atom

Subatomic Particles

What are the 3 types of subatomic particles?

Protons

Neutrons

Electrons

Protons

Represented as: p+

Have a +1 electrical charge “Positive Protons”

Have a relative mass of ~ 1 amu (atomic mass unit)

Located in the atom’s nucleus

Neutrons

Represented as: n

Has no electrical charge “No charge neutrons”

Has a relative mass of ~ 1 amu (atomic mass unit)

Is located in the atom’s nucleus

Electrons

Represented as: e-

Has a -1 electrical charge ‘egative electrons

Has a relative mass of ~ 1/2000 amu (atomic mass units)

It is located in the region around the nucleus

Comparing the 3 Subatomic Particles

Symbol Electrical Charge

Relative Mass

Location in the Atom

What it accounts for

Protons p+ +1 1 Nucleus Mass of the atom

Neutrons n 0 1 Nucleus Mass of the atom

Electrons e- -1 1/2000 Around the nucleus

Volume of the atom

Anatomy of an Atom

NEUCLEUS = center of the atom; contains the PROTONS and NEUTRONS

ELECTRONS = moving around the nucleus in organized energy levels

Atomic Number and Mass

Atomic Number = the number of p+ found in the nucleus This number never changes

Atomic Mass = the number of p+ and n found in the nucleus So the number of neutrons is

the atomic mass - the atomic number

Neutral Atoms

There are the same number of p+ in an atom as e-

Protons give the atom a positive charge

Electrons give the atom a negative charge

Together, these two charges cancel each other out, making the atom neutrally charged

Example: Potassium (K) has an atomic number of 19. That means there are 19 protons in the nucleus. That means there are also 19 electrons in the atom.

Practice!

For Boron: What is the atomic number? What is the atomic mass? How many protons are in the

atom? How many neutrons are in the

atom? How many electrons are in the

atom?

12

5

10.81

5

10.81 Round to the nearest whole # 11 – 5 = 6

5

Practice!

For Silicon: What is the atomic number? What is the atomic mass? How many protons are in the

atom? How many neutrons are in the

atom? How many electrons are in the

atom?

13

14

28.086

14

28.086 Round to the nearest whole # 28 – 14 = 14

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Nuclear Charge

Nuclear Charge = the electrical charge on the nucleus

Since the protons are the only subatomic particle in the nucleus with a charge, the nuclear charge = the number of protons

Atomic # = # of p+ = nuclear charge

The atomic number for Carbon is 6. That means there are 6 protons in the nucleus. That also mean that the nuclear charge is +6.

What are the nuclear charges on the rest of these elements?

Review

What are the charges on the subatomic particles?

What particle(s) account for the atom’s mass?

What particle(s) account for the atom’s volume?

What is a neutral atom?

Homework Read pg. 170-171 Complete the Atomic Structure WS

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Protons positiveElectrons negativeNeutrons neutral

Protons and Neutrons

Electrons

Protons = Electrons