SamStudies
SCH 3UP Final Exam Review 2019
Made by SamStudies on Stuvia
Unit 1: Matter and Chemical Bonding
Click Here for the Unit 1 Quizlet
Atomic Theories
Dalton’s Atomic Theory (1808)
● Suggested atoms were like billiard balls
● Based on:
○ All matter is made up of particles called atoms
○ All atoms of an element are identical
○ Atoms are unique to their element
○ Atoms can be rearranged to form new substances
○ Atoms cannot be destroyed
Thomson’s Discovery of the Electron (1897)
● Used the Cathode Ray Tube Experiment to make his discovery
● Developed the Plum Pudding Model
○ Within an atom the protons and electrons are scattered inside
Rutherford’s Discovery of the Nucleus (1911)
● Shot tiny alpha particles at a piece of gold foil one particle thick
○ The positive rays deflected slightly
■ If electrons were distributed throughout the atom, they would pass straight
through
● Proposed a new model of a dense positively charged nucleus with electrons orbiting
around
Chadwick’s Discovery of the Neutron (1932)
● If the atom had only positive and negative charges, it would collapse due to attraction
● Predicted a neutral particle, the neutron to keep the atom together
Bohr’s Proposal of Energy Levels
● Electrons have defined energy levels
● Noticed that hydrogen emitted a certain spectrum and this would change as it was excited
with energy
● Now arrived at our current planetary model
, SamStudies
Isotopes and Isotopic Abundance (1.4)
Isotope: a form of an element in which the atoms have the same number of protons as all
other forms of that element, but a different number of neutrons
● For example: Carbon-12 and Carbon-14
○ Carbon-12: 6 protons, 6 electrons and 6 neutrons
○ Carbon-14: 6 protons, 6 electrons and 8 neutrons
Isotopic Abundance: the percentage of a given isotope in the sample of an element
● Measured using a mass spectrometer
● Can calculate the average atomic mass of an element using the isotopic masses and
abundances
○ Formula: Average = (Isotopic Mass 1)(Abundance of Isotope 1) + (Isotopic Mass
2)(Abundance of Isotope 2)...
Ex:
Mass Number Abundance
Hf-176 5%
Hf-177 19%
Hf-178 27%
Hf-179 14%
Hf-180 35%
Average = (176)(0.05) + (177)(0.19) + (178)(0.27) + (179)(0.14) + (180)(0.35)
Average = 178.55 Amu
Radiation and Radioisotopes (1.4)
Radioisotope: an isotope that spontaneously decays to produce two or more smaller nuclei
and radiation
● Goes through Radioactive Decay
Radioactive Decay: the spontaneous disintegration of unstable isotopes
● Emits nuclear radiation
SCH 3UP Final Exam Review 2019
Made by SamStudies on Stuvia
Unit 1: Matter and Chemical Bonding
Click Here for the Unit 1 Quizlet
Atomic Theories
Dalton’s Atomic Theory (1808)
● Suggested atoms were like billiard balls
● Based on:
○ All matter is made up of particles called atoms
○ All atoms of an element are identical
○ Atoms are unique to their element
○ Atoms can be rearranged to form new substances
○ Atoms cannot be destroyed
Thomson’s Discovery of the Electron (1897)
● Used the Cathode Ray Tube Experiment to make his discovery
● Developed the Plum Pudding Model
○ Within an atom the protons and electrons are scattered inside
Rutherford’s Discovery of the Nucleus (1911)
● Shot tiny alpha particles at a piece of gold foil one particle thick
○ The positive rays deflected slightly
■ If electrons were distributed throughout the atom, they would pass straight
through
● Proposed a new model of a dense positively charged nucleus with electrons orbiting
around
Chadwick’s Discovery of the Neutron (1932)
● If the atom had only positive and negative charges, it would collapse due to attraction
● Predicted a neutral particle, the neutron to keep the atom together
Bohr’s Proposal of Energy Levels
● Electrons have defined energy levels
● Noticed that hydrogen emitted a certain spectrum and this would change as it was excited
with energy
● Now arrived at our current planetary model
, SamStudies
Isotopes and Isotopic Abundance (1.4)
Isotope: a form of an element in which the atoms have the same number of protons as all
other forms of that element, but a different number of neutrons
● For example: Carbon-12 and Carbon-14
○ Carbon-12: 6 protons, 6 electrons and 6 neutrons
○ Carbon-14: 6 protons, 6 electrons and 8 neutrons
Isotopic Abundance: the percentage of a given isotope in the sample of an element
● Measured using a mass spectrometer
● Can calculate the average atomic mass of an element using the isotopic masses and
abundances
○ Formula: Average = (Isotopic Mass 1)(Abundance of Isotope 1) + (Isotopic Mass
2)(Abundance of Isotope 2)...
Ex:
Mass Number Abundance
Hf-176 5%
Hf-177 19%
Hf-178 27%
Hf-179 14%
Hf-180 35%
Average = (176)(0.05) + (177)(0.19) + (178)(0.27) + (179)(0.14) + (180)(0.35)
Average = 178.55 Amu
Radiation and Radioisotopes (1.4)
Radioisotope: an isotope that spontaneously decays to produce two or more smaller nuclei
and radiation
● Goes through Radioactive Decay
Radioactive Decay: the spontaneous disintegration of unstable isotopes
● Emits nuclear radiation
