Intro to the Atomic Theory
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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
14
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
15
Protons positiveElectrons negativeNeutrons neutral
Protons and Neutrons
Electrons
Protons = Electrons
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