Lecture 3 Flashcards
basic building blocks of matter
atoms
Atomic Theory of Matter:
List 5 key concepts that describe atoms
- all matter is made up of atoms
- all atoms of the same element are similar but they are significantly different from atoms of another element
- the number and arrangements of atoms determines a substance’s identity
- chemical change is rearrangement of atoms to give a new substance
- only whole atoms participate in a chemical change (can’t be broken down)
2 Las that fall under Dalton’s Atomic Theory
Law of Conservation of Matter
Law of Definite Proportions
the elements in a compound are always present in definite proportions
Law of Definite Proportions
matter is neither lost nor gained during a chemical reaction
Law of Conservation of Matter
True/False: the composition of a pure substance is not constant
FALSE! IT IS CONSTANT!
building blocks of atoms
subatomic particles
3 subatomic particles
electrons
protons
neutrons
where are the protons and neutrons located in an atom
the nucleus
where are the electrons located in an atom
extranuclear
Movement of electrons determine _____ of an atom
size
The protons and neutrons = ______% mass of an atom
99.9%
The protons are equal to the _______ on and element on the periodic table
atomic number
How to determine the number of electrons of an element
it’s the same as the number of protons
How to determine the number of neutrons of an element
atomic mass - # protons
atoms of same electron with different # of neutrons
isotope
True/False: all atoms of an element must have different # of protons, but can also differ # of neutrons
FALSE! all atoms of an element must have the same # of protons, but can vary in # of neutrons
average of different isotopes atomic masses
atomic weight
repeating according to some patter
periodic
when elements are arranged in the order of increasing atomic #, their chemical and physical properties show repeatable trends
periodic law
Where are representative elements located on periodic table
the “A” group
Where are the transition elements located on the periodic table
the “B” group
True/False: halogens are always colored
FALSE! halogens are NOT always colored
True/False: most metals are red
FASLE! most metals are gray
Electron Shell Capacity
1st shell = 2 2nd shell = 8 3rd shell = 18 4th shell = 32 5th shell = 50 6th shell = 72 7th shell = 98
- shells 3…. overlap in energy
subshells and their capacity
s = 2 e-, 1 orbital p = 6 e-, 3 orbital d = 10 e-, 5 orbital f = 14 e-, 7 orbital
describes the arrangement of e- in an atom
- because an e-‘s energy is ______ it can have only specific values
quantum mechanics
Who showed that atoms are mostly empty space
Rutherford
Who found the charge to mass ratio of e-
Thomson
Who showed that the charge on any particle is a multiple of the charge on an e-
Millikan
