Intro to the Atomic Theory Elements, 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 SymbolElectrical Charge Relative Mass Location in the Atom What it accounts for Protonsp++11NucleusMass of the atom Neutronsn01NucleusMass of the atom Electronse-1/2000Around 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? 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? 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 Complete the Atomic Structure WS 15 Protons positive Electrons negative Neutrons neutral Protons and Neutrons Electrons Protons = Electrons