Chapter 2 Flashcards
Define the “Law of Mass Conservation”.
The total mass of a substance does not change during a chemical reaction.
Define “Law of Definite Composition”.
No matter where it comes from, a specific compound is composed of the same elements in the same parts by mass.
Define “Law of Multiple Proportions”.
States that if you have two elements that can form two different compounds, the different masses can be expressed as a ratio of a small whole number.
Know the Postulates of the Atomic Theory.
- All matter consists of atoms.
- Atoms of one element cannot be converted into atoms of another element.
- Atoms of an element are identical in mass and other properties- and these are different from atoms of any other element.
- Compounds result from the chemical combination of a specific ratio of atoms from different elements.
The discovery of the electron and its properties can be credited to who?
J.J. Thompson
The cathode rays in the “Cathode Experiment” consist of what?
Negatively charged particles.
Robert Millikan what with the “oil drop experiment”?
The charge of the electron.
What did Ernest Rutherford discover?
Discovered the nucleus that contained protons.
You can use the atomic number (Z) & mass number (A) to find what?
Atomic number (Z) are the number of protons.
Mass number (A) are: Protons+Neutrons
What are isotopes?
Atoms that have different numbers of neutrons and therefore different mass numbers.
How are “oxoanions” formed?
An element, usually a nonmetal, is bonded to one or more oxygen atoms.
What is a pure substance?
Elements that will always have a fixed ratio.
