Download Atomic Structure Study Guide

Atomic Structure Study Guide
Dr. Slotsky & Mrs. Mingels Chemistry I
Part I. Dalton and Atomic Theory
Philosophers have hypothesized that matter was made up of tiny particles called ______ since
the times of _____________________. However, these speculations were not scientific theories,
because they were not based on any experimental ____________. The first scientific theory of atoms
was developed by ___________ in the 18th Century. He based his theory on 3 scientific _____ which he
had observed during chemical experiments. They were the Law of Conservation of ____, the Law of
Definite _____________, and the Law of __________ Proportions.
The Law of Conservation of Mass states that the total mass of the reactants is equal to the total
mass of the products of any chemical reaction – mass is ___________ in all chemical reactions.
The Law of __________ Proportions states that a compound always has the same proportions,
by mass, of the elements which make it up.
The Law of Multiple Proportions only applies when the same 2 _________ can produce multiple
compounds (for example, H2O and H2O2): it states that the proportions by mass of the elements in the
two compounds are related by small whole numbers.
Word Bank: John Dalton, mass, Definite, evidence, elements, conserved, proportions, multiple,
laws, ancient Greece, atoms
Part II. Dalton’s Principles - Dalton’s atomic theory can be summarized as five principles.
(1) All matter is composed of extremely small, indivisible particles called ______, which cannot be
created or destroyed.
(2) Atoms of a given element are ___________ in all ways.
(3) Atoms of different elements have different physical and chemical __________.
(4) Atoms of different elements combine in simple, whole-number ratios to form _________.
(5) In chemical reactions, atoms are rearranged, but are never __________ or destroyed.
Word Bank: identical, properties, atoms, compounds, created
Part III. Thomson’s Cathode Rays, Rutherford’s Gold Foil Experiment, Spectral emissions
Thomson discovered that a beam of cathode rays – particles emitted from the _______ of a
high voltage vacuum tube – was made up of ____________ charged particles, which had a
smaller mass/charge ratio than any known atom. This showed that ______________ particles
existed, and therefore atoms were not indivisible. These particles are now known as
_____________. His student, Rutherford, shot alpha particles at a thin ____________ and
discovered that most of the mass of an atom was located in a small, positively charged core.
This is now known as the _____________, and is made up of tightly packed positively charged
___________ and neutral __________. The reason hydrogen glows a specific color is because
energy is added to electrons in the
state (lowest energy levels) causing them to move
to higher energy levels in the
state. When the energy is released they fall back
down to their lowest state and release energy as
.
Word Bank: light, negatively, ground, cathode, excited, subatomic, protons, neutrons,
electrons, nucleus
Part IV. The Bohr Model of the Atom
Example: A sodium (Na) atom
__ protons
__ neutrons
The nucleus of a sodium (Na) atom has 11 protons because
the ATOMIC NUMBER is 11. The atom has a total ATOMIC MASS of approximately 23 – there
must be
neutrons along with the 11 protons to give a total mass of 23 amu (atomic mass
units)
Sodium has
electrons to balance the 11 protons because the total charge must be
neutral. These electrons are arranged in shells by the electron configuration 2-8-1: 2 electrons
in the first (innermost) shell, 8 electrons in the second shell, and 1 in the third shell.
Draw in the electrons on the diagram above for a sodium atom.
Fill in the boxes in the table below for each of the atoms.
Symbol Name
Atomic # Mass
Charge # Protons # Neutrons # Electrons
Sodium
23amu 0
P-3
31amu
16
Part V. States and their changes
Substances in the
state have neither a fixed volume nor a fixed shape. If they
change into a
, they will have a fixed volume, but still not a fixed shape. This
change is called
. If they change back it would be called
.
Substances in the
state have both a fixed shape and volume. If they turn to a
liquid it’s called
, if instead they turn directly into a gas it’s called
.
Liquids turn into a solid by
. Gases turn directly into solids by
. A
is a super heated gas formed in a process called
. The process by
which energy is released and it turns back into a gas is called
.
Word Bank: liquid, gas, solid, melting, boiling, freezing, sublimation, deposition, ionization,
recombination, condensation, evaporation THEN LABEL THE CHANGES IN THE DIAGRAM
Solid
Plasma
Liquid
Gas
Liquid