Chemistry Semester 1 study guide
Chemistry (Chapter 4-9, 12)
*Ionic compounds have relatively high melting temperatures.
*Know about polar bonds, nonpolar bonds, avogadro’s number, and calculating the atomic mass (unit?)
*
Chapter 4: Basically about theories of atoms and the atom itself
4-1: Theories
The Greeks believed that all matter was composed of earth, fire, air and water.
Democritus: the first person to propose the idea of atoms (that matter was not infinitely divisible): atomos. “Atoms are solid, homogenous, indestructible and indivisible.”
Aristotle - DENIED IT. He is why Democritus’ atomic theory was rejected and why that theory hasn’t been expanded on for 2000 years until…
John Dalton: revived/revised D’s ideas called: Dalton’s Atomic theory which basically states that all matter are composed of extremely tiny atoms, all atoms of a given element are identical (same size, mass, and chemical properties), atoms cannot be created, divided into smaller particles, or destroyed (similar to the Law of Conservation of Mass), different atoms combine in simple whole-number ratios to form compounds (see below), in a chemical reaction, atoms are separated, combined, or rearranged.
Whole-number ratios: No halfsies.
But he was wrong about atoms being indivisible (that’s how we know about protons and neutrons and electrons and the other subatomic particles).
And how atoms of the same element have identical properties: atoms of an element may have slightly different masses, e.g: ISOTOPES.
You can see an atom using the scanning tunneling microscope.
4-2: Discovering subatomic particles and Nuclear particles (alpha, beta, gamma)
Discovering the electron was a complete accident
Cathode ray tube: used by Sir William Crookes. He discovered the cathode ray.
They discovered that those cathode rays were a stream of negatively charged particles which they called electrons. The exact value of the negative charge was not known (was it 2-, 3-, 9-, 1-?).
J.J. Thomson, by measuring
*Ionic compounds have relatively high melting temperatures.
*Know about polar bonds, nonpolar bonds, avogadro’s number, and calculating the atomic mass (unit?)
*
Chapter 4: Basically about theories of atoms and the atom itself
4-1: Theories
The Greeks believed that all matter was composed of earth, fire, air and water.
Democritus: the first person to propose the idea of atoms (that matter was not infinitely divisible): atomos. “Atoms are solid, homogenous, indestructible and indivisible.”
Aristotle - DENIED IT. He is why Democritus’ atomic theory was rejected and why that theory hasn’t been expanded on for 2000 years until…
John Dalton: revived/revised D’s ideas called: Dalton’s Atomic theory which basically states that all matter are composed of extremely tiny atoms, all atoms of a given element are identical (same size, mass, and chemical properties), atoms cannot be created, divided into smaller particles, or destroyed (similar to the Law of Conservation of Mass), different atoms combine in simple whole-number ratios to form compounds (see below), in a chemical reaction, atoms are separated, combined, or rearranged.
Whole-number ratios: No halfsies.
But he was wrong about atoms being indivisible (that’s how we know about protons and neutrons and electrons and the other subatomic particles).
And how atoms of the same element have identical properties: atoms of an element may have slightly different masses, e.g: ISOTOPES.
You can see an atom using the scanning tunneling microscope.
4-2: Discovering subatomic particles and Nuclear particles (alpha, beta, gamma)
Discovering the electron was a complete accident
Cathode ray tube: used by Sir William Crookes. He discovered the cathode ray.
They discovered that those cathode rays were a stream of negatively charged particles which they called electrons. The exact value of the negative charge was not known (was it 2-, 3-, 9-, 1-?).
J.J. Thomson, by measuring