Chapter 2 Flashcards
Atoms, Molecules, and Ions (19 cards)
Law of Constant Composition
a. In a given compound, the relative numbers and kinds of mass are constant
Law of Conservation of Mass
a. The total mass off materials present after a chemical reaction is the same as the total mass present before the reaction
Law of Multiple Proportions
a. If two elements A and B combine to form more than one compound, the masses of B that can combine with the given mass of A are in the ratio of small whole numbers
Daltons Atomic Theory
a. Each Element is composed of extremely small particles called atoms
b. All atoms of a given element are identical, but the atoms of one element are different from the atoms of all other elements
c. Atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions
d. Compounds are formed when atoms of more than one element combine (nitrogen and Oxygen) ; a given compound always has the same relative number and kind of atoms.
Atom
a. Atoms are composed In part of electrically charged particles, some with a positive charge and some with a negative charge.
IMPORTANT FACT
- Particles with the same charge repel one another, whereas particles with unlike charges attract one another.
Cathode Rays and Electrons
a. Radiation produced between electrodes are known as Cathode Rays
i. Although rays were not be able to be seen, they were detected because certain materials/chemicals caused the substance to give off light.
ii. Cathode rays are the same regardless of the cathode material
iii. Cathode rays are streams of negatively charged particles known as the electron
iv.
(C = Coulomb which is the SI unit for electrical charge)
v. The electron’s mass is 2000 times smaller than that of hydrogen, the lightest atom
Alpha
- Bent by an electric field in opposite directions
- Fast moving particles
- Positive charge and attracted to a negative plate
- Charge of 2+
Beta
- Bent by an electric field in opposite directions
- Fast moving particles
- These fast moving particles are high speed electrons and can be considered the radioactive equivalent of cathode rays
- Attract to a positively charged plate
- Charge of 1-
Gamma
- Unaffected by the electric field
- Does not consist of particles
- Carries no charge
IMPORTANT
- Every atom has an equal number of electrons and protons, so atoms have no net electrical charge
Atomic Number
i. Each element has a characteristic number of protons
1. The number of protons in an element
ii. The atomic number is the number of protons in an atom
iii. Atoms have no net electrical charge, so the amount of electrons in a atom = the amount of protons
Mass Number
i. Atoms of any element can differ in the number of neutrons as well as mass
ii. Mass number is the number of protons plus neutrons in the atom
Periods
i. Horizontal rows (1A, 2A, 3A….1B, 2B all until 8B)
Elements
i. Arranged in order of increasing atomic number
Groups
i. Vertical columns
ii. Labeled with similarities between elements
1. 1A = Alkali Metals (everything excluding Hydrogen)
2. 2A = Alkaline earth metals
3. 6A = Chalcogens (unneeded)
4. 7A = Halogens (everything excluding Nitrogen)
IMPORTANT
- All metallic elements except mercury are solid at room temperature
Metallic Elements
i. Share characteristic properties
1. Luster
2. High Electrical
3. Heat Conductivity
