CHEMISTRY Flashcards
Democritus
Democritus came up with the first ideas of an atom. His theory was not used because he could not explain what held atoms together.
What is special about an element?
It cannot be broken down. Simplest form. Each element is unique because of the amount of protons
4 parts of Dalton’s Atomic Theory of Matter
-All matter is made of atoms.
-All atoms of the same elements have the same properties.
-Compounds are formed when atoms of two different elements join together
-A chemical reaction is a rearrangement of atoms.
What is a anion?
Molecules with a negative charge.
What is a cation?
Molecules with positive charges.
What did Thomson find?
Thomas discovered opposites attract, and the exact charge of electrons. (cathlode ray tube)
How did Thomson discover his findings?
A cathode ray tube.
What was Thomson’s model of an atom called?
“Plum pudding model”
Why was Thomson’s model important if it was wrong?
Even though the model was wrong, it was a large development of Atom theory history.
What did Millikan do?
Millikan conducted an oil drop experiment.
Why was the oil drop experiment important?
Millikan discovered the mass of an electron.
What was Rutherford’s experiment?
He shot alpha particles at gold foil.
What did Rutherford discover in his experiment?
He saw that some particles bounces back at him. He discovered the nucleus of an atom.
How does an ion form?
An ion forms when an atom gains or loses electrons.
What is an Isotope?
Atoms that have the same number of protons and electrons but different numbers of neutrons.
What is atomic mass?
average mass of isotopes
What is a atomic #?
Number of protons in an atom
Mass number?
Sum of protons and neutrons.
Four characteristics of a wave:
Wavelength, frequency, aptitude, and speed.
What kind of electromagnetic radiation has the shortest wave?
Gamma-Rays
Who came up with the photo-electric effect?
Einstein
How does white light become colored light?
When white light strikes a prism and is bent to create different colors of light.
What causes the color black?
Black is the ABSENCE of light
Why does a line spectrum occur?
A line spectrum occurs because atoms have energy levels available for electrons
to orbit in.
What did Heisenberg come up with?
The uncertainty principle
What does the uncertainty principle explain?
It is impossible to know the position and speed of a particle with perfect accuracy.
The 4 orbitals are:
S
P
D
F
What is the Aufbau principle?
electrons fill lower-energy atomic orbitals before filling higher-energy ones
What is Hund’s rule?
All orbitals must be by themselves first before any orbitals are doubled.
What is the Pauli Exclusion principle?
If electrons are paired together, they must be in different directions.
Photo-electric effect?
is when light shines on a surface and electrons are ejected from the surface.
What do polarizers do?
is a filter that lets in specific light waves pass through while blocking light.
what does diffraction grating do?
Bends light as it passes through.
