Chapters 4&5 Flashcards
(29 cards)
What did Democritus contribute?
The idea of indivisible atoms
What are models used for?
To observe things too big, too small, too complex, the relationships among various objects, and things that are difficult to observe.
What did John Dalton contribute?
- ) Elements are made up of indivisible atoms which can’t be changed into other elements
- ) Atoms of the same element are exactly alike
- ) Atoms of different elements can join different to form different compounds
Was John Daltons theory correct?
No
What did JJ Thompson contribute?
- The Plum Pudding
- The idea of electrons
What did Ernest Rutherford contribute?
- The idea of a Nucleus
- Gold Foil Experiment
What are the charges of Protons, Nuetrons, and Electrons?
Positive, Neutral, and Negative
How do you find the numbers of Nuetrons in an atom?
Mass # - Atomic #
What are isotopes?
An element with the same number of Protons but with a different number of Nuetrons
What did Neil’s Bohr contribute?
The idea that electrons orbit in circular orbits around the nucleus like planets
What must happen to an electron if it moves into a higher/lower energy level
It must gain/lose energy
Was Bohrs model correct?
No
What did Erwin Schrooder contribute?
The Electron Cloud Model (The Quantum Mechanical Model)
What is the Electron Cloud Model?
The regions in an atom where electrons are found called orbitals. Theses orbitals are clouds of probability where electrons may be found
What is a Valence Electron?
Electrons in the outermost shell of an atom
What determines the chemical properties of an element?
Valence Electrons
What did Dmitri Mendeleev contribute?
He created the periodic table based on repeating properties and by atomic mass
What is the Periodic Law?
When elements are arranged in order of their number of protons, there is a periodic repetition of their physical and chemical properties
What do all elements strive to have?
8 Valence Electrons
What do all elements want to become?
Noble gases
What group are the noble gasses?
8
What is ionization?
The process of adding or losing electrons
What is an ion?
An atom or group of atoms that has lost or gained electrons
What is a cation?
Ion with a positive charge
