Chapter 2 Flashcards
the law of constant composition
substance changes its physical appearance but not its composition:
law of conservation of mass
The total mass of materials present after a chemical reaction is the same as the total mass present before the reaction.
law of multiple porportions
If two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers.
Who discovered atomic theory of matter?
daltons atomic theory
What are cathode rays?
streams of electrons that are produced when a high voltage is applied to electrodes in an evacutaed tube
What did thompson theorize?
described cathode rays as streams of negatively charged particles that we now call electrons.
What did thomson discover?
electrons
What is radioactivity?
spontaneos emission of radiation
Who discovered the different types of radiation?
rutherfrod
What are three types of radiation?
alpha, beta, and gamma
What happens paths of beta and alpha radiation when it goes through an electric field?
bent in the opposite direction
what happens to the path of gamma radiation as it goes through an electric field
unaffected
What are beta particales?
high-speed electrons that can be considered the radioactive equivalent of cathode rays.
Are beta particles negative or positive?
negative charge
What is beta particles attracted to?
positiviely charged plates
Are alpha particles positive or negative?
positive charge
What are the alpha particles attracted to?
the negative plate
What charge does beta particles have?
-1
what charge does alpha particles have?
+2
Does gamma radiaton have a charge?
no
What did thomson theorize on the model of the atom?
atom consists of a uniform postivie sphere of matter in which the mass is evently distributed in which the electrons are embedded in it
what did thomson call his model of the atom?
plum-pudding model
what was rutherford model called?
nuclear model
What was the nuclear model?
the mass of each gold atom and all of its positive charge reside in a very small, extremely dense region that he called the nucleus.
He postulated further that most of the volume of an atom is empty space in which electrons move around the nucleus.
How many m is in 1 Å
1 x 10^-10
Why are electrons attracted to the protons?
electrostatic forces between particles of opposite electrial charges
List the particles in smallest to greatest mass?
Protons=Neutrons>Electrons
Where is the mass number located?
subscript at the top
What is the mass number
protons+neutrons
How to find the atomic weight when given the isotpoes?
(% of isotope x mass)+ if there is another isotope the same thing.
Which group is the alkali metals in?
1A
What group is the alkaline earth metals in?
2A
what group is the chalcogens in?
6A
What group is the halogens in?
7A
What are the characteristic properties of metals?
luster, high electrical and heat conductivity, solid at room temp but Hg
What are characteristcs of nonmetals?
some are gaseous, solid, one is liquid
What are diatomic molecules?
a molecule made up of two atoms
what are the 7 diatomic molecules
H,O,N,F,Cl,Br,I
What are molecular compounds?
Compounds composed of molecules that contain more than one type of atom are