Download Unit 1- Matter and Energy 1

ATOM – Notes Outline for Review
Atom:
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The smallest component of an ______________.
So if there are103 different elements there are 103 _____________ __________ of atoms.
Subatomic Particles
• Protons
o Mass = _____ AMU
o Charge = _________
• Neutrons
o Mass = _____ AMU
o Charge = _________
• Nucleons are all of the particles in the _____________ (_____________ and _____________)
• Electrons
o Mass = _____ AMU
o Charge = _________
Atomic Theories
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Dalton
• Elements are composed of extremely small particles called ________________.
• All atoms of a given element have ______________ properties.
• Compounds are formed when atoms of different elements combine with one another in ________ _______
numbers.
• The relative numbers and kinds of atoms are _______________ in a given compound.
JJ Thompson
• Atom can be divided into parts. One of which is an ____________.
• These are _________________ charged particles ______________ in a positively charged atom.
• Raisins embedded in plum pudding
Rutherford
• An atom contains a ___________ ______________ charged nucleus accounting for the majority of its mass.
• The rest of the atom is mostly _____________ _____________ where the electrons are.
• Determined this theory after performing the gold-foil experiment.
o Rutherford directed __________ particles (radioactive source) which are ____________ charged and
smaller than atoms at a thin piece of gold foil.
o He expected all the alpha particles to pass through (detected by the fluorescent screen) with just a few
being slightly defected.
o _____________ of the particles did go straight through proving that atoms are mostly empty space.
o A few were slightly deflected. BUT, some were greatly deflected. They were strongly _____________
by a dense, positive, central core and bounced back
Bohr
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Electrons are located in specific ___________ around the nucleus.
Each electron must contain a certain amount of energy to stay in its orbit. The ________________ the electron is
from the nucleus, ______________ _____________ it contains.
Wave-Mechanical Model
• Previously matter was considered a particle and energy was considered a wave.
• This current model predicts that matter and energy can act like ________ or _________ – Dual Nature Concept
• In this model (aka - the electron cloud model), the electrons are in ____________, which are defined as regions
of ___________ ______________ _______________ ______________.
Bohr’s Model versus the Wave – Mechanical Model
• The difference is in the description of _____________ _________________ around the nucleus.
• Bohr suggested well ___________, ______________ orbits.
• The wave-mechanical model shows electrons located around the nucleus in orbitals.
• An orbital is a region in which an electron with a certain amount of energy is most likely to be located (like a
_____________).
Atomic Number
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Equals the number of ______________ in an atoms nucleus.
It identifies the element.
It _______________ changes unless the element has changed.
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All atoms of Lithium will have ________ Protons.
Mass Number
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Equals the number of ________ + _________ in the _____________.
Can be determined by ______________ the decimal (atomic mass) to the nearest whole number.
Does NOT _____________ the element.
Li : mass # = 7
The # of neutrons in the nucleus can change thus ________ # can change.
Atomic Mass
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Decimal
Average of all the ______________ that occur in ___________.
Atoms with the same protons but with a different number of neutrons.
C-12, C-13, C-14 - All carbon atoms have 6 _____________ and 6,7, or 8 ______________.
Steps required to calculate atomic mass
o Convert _____________ into _______________
o Calculate the contribution of each isotope to the atomic mass by multiplying the decimal percentage by the
________ # for each isotope.
o Add them together to get the ______________ average for the atomic mass.
Electrons
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Found in energy levels around the nucleus (orbitals according to the wave-mechanical model)
Negatively charged
Very, Very, Very small
When atoms are neutral (no charge), protons _________________electrons, Na________.
Can be gained or lost from the outer most energy level. This is called the ______________ ______________
________________ electrons are found in the valence shell.
o These are responsible for most _____________ _____________ and in the formation of __________________.
o Every atom wants __________ valence electrons (unless it has only 1 energy level, then it wants only _______).
o In general, the number of valence electrons affects the _______________ properties of an element.
o Valence electron # = ___________ # on the ___________ ___________.
Each electron in an atom has its own distinct amount of _______________ which depends on their orbital or how far they
are from the nucleus.
o Electrons in orbitals closer to the nucleus have ___________ energy and are __________ stable
o Electrons in orbitals further from the nucleus have ____________ energy and are ________ stable
o When all electrons in an atom are in their lowest possible energy level, the atom is at its ________ state.
The number of electrons found in each orbital when an atom is at the ground state can be found on the periodic table. This
is the atoms _____________ ____________________.
Ions
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Cations
• Sodium has _____________ orbits (Bohr Model)
• The third orbit has ___________ electron.
• To be more ______________, sodium will give away the one electron it has in the third orbit or it could receive
7 more electrons from another atom in order for it to have ___________ electrons on the outer orbit.
• Both processes would have sodium ending up with 8 electrons on its outer orbit.
• Giving away 1 electron is _________________ than receiving 7 electrons.
• Sodium will lose 1 electron which means that it now has 10 electrons and 11 protons.
• It has 1 less electron than proton so it’s charge is _____________. The charge is also referred to as its oxidation
number.
• The equation showing the lose of an electron is _____________________________________
• Cations are _______________ in size than atoms.
Anions
• Oxygen has ____________ orbits (Bohr Model).
• The second orbit has ________________ electrons.
• To be more stable, oxygen will give away all the 6 electrons in the second orbit or receive 2 more electrons from
another atom.
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Both processes will lead to oxygen having _______________ electrons on its outer orbit.
Receiving 2 more electrons from another atom is easier than giving away all its 6 electrons.
Oxygen will receive 2 more electrons which means it now has ____________ electrons and _________ protons.
It has 2 more electrons than protons so it’s charge is _______________. The charge is also referred to as its
_______________ _________________.
The equation showing the gaining of electrons is _____________________________________
Anions are __________________ in size than atoms.
Lewis Dot Diagrams
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Shows only __________________ ______________ for the element.
Steps for drawing them
o Write the elemental symbols for the atoms
o Fill in the electrons
 If more than 2, place 1 electrons at each side of the element symbol and then double up as needed.
 If there are 2 valence electrons, place both of them on the ________ __________ of the element
symbol.
Cations have ____________ electrons in the outermost orbital.
Anions have ___________ in the outermost orbital.
Atomic Spectra
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Electrons ______________ energy to become EXCITED
• When an electron in an atom gains a specific amount of energy, the electron becomes ____________ and jumps
to a ________________ energy level (orbital).
• The energy can come from outside sources like _____________, ___________, ______________.
• Copper is absorbing energy from a Bunsen burner flame and the flame turns _____________.
• The _________________ state configuration changes.
• But the ______________ number of electrons stays the same.
• The wavelengths of energy that are absorbed can be seen in an _______________ spectra as black lines in a
colorful background.
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Electrons _____________ energy to go back to the Ground State
• After jumping to a higher level, the electron will very quickly return to its ______________ level.
• The energy they previously absorbed is now released as infrared, ultraviolet, or visible ___________.
• This ______________ energy can be used to ____________ an element.
• Copper emits blue light as its electrons return to the ground state.
• The wavelengths of energy that are emitted can be seen in an _______________ spectra as colorful lines in a
black background.