Structure of an Atom 4.2
Properties of Subatomic Particles
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What are the building blocks of matter? What are atoms made of? _______________,
_______________, and _______________, are subatomic particles. Rutherford found that the
_______________ _______________, varies among elements and that the
______________must contain at least one particle with a ______________________________.
He named these particles _______________.
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A proton is a ______________________________subatomic particles found in the
______________of an atom. Proton’s have a _______________of ________
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Protons, Neutrons and Electrons
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The particles Thomson detected in his experiments were name _______________. An
_______________is a _______________charged subatomic particle found in the
_____________________________________________Electrons has a charge
_______________.
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______________________________designed an experiment to show that neutrons existed.
(Rutherford predicted them). He found they had a ______________________________. A
_______________is a _______________subatomic particle found in the _______________of an
atom (charge =____). Neutrons have a mass almost equal to a _______________.
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Comparing Subatomic Particles
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Properties of Subatomic Particles
Particle
Symbol
Charge
Electron
Proton
Neutron
Atomic Number & Mass Number
Mass
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Atoms of any given element always have the
_____________________________________________.
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Ex: one proton in the nucleus of each hydrogen atom. Hydrogen has been assigned the
______________________________1.The ______________________________of an element
equals the _______________of _______________in an atom of that element. Atoms of
different _______________have _______________numbers of _______________. Sulfur has
an atomic number of 16 because it has 16 _______________. Each positive charge in an atom
is _______________by a ______________________________ The atomic number is then also
equal to the number of ________________.
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If hydrogen has an atomic number of one, how many electrons does it have? _______________
If Sulfur has 16 protons, how many electrons does it have? _______________
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Mass Number
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How can you find the number of neutrons in an atom? The
______________________________is the sum of the protons and neutrons in the nucleus of
that atom. An atom of aluminum with 13 protons and 14 neutrons has a mass number of 27. If
you know the ______________________________and the ______________________________,
you can find the number of neutrons by _______________.
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Isotopes
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In _______________atomic theory, all the atoms of a given element are _______________. We
now know that every atom of a given element _______________have the same number of
neutrons. _______________are atoms of the _______________element with
_______________numbers of _______________and therefore different
_______________numbers. Still have the same _______________.
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Isotope Example
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Ex: Oxygen has 8 protons. Some oxygen atoms have 8 neutrons and a mass number of
16. Other atoms have 9 neutrons and a mass number of 17.
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Uranium-238 has a mass number of _______ and ________ neutrons in the nucleus
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Uranium-235 has _______ neutrons. What is the atomic number of uranium? ______
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Isotopes
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Most isotopes have the same properties as other variations of the same element.
_______________however, is an exception. Hydrogen-1 has ____ neutrons; Hydrogen-2 has ___
neutrons; Hydrogen-3 has ____ neutrons. Since hydrogen-1 has only one proton, adding a
neutron _______________it’s mass. Water with hydrogen-2 atoms is called _______________.
Heavy water has different properties than Hydrogen-1
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Compare and Contrast
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How are the compositions of heavy water and ordinary water similar?
What type of hydrogen atoms does ordinary water contain?
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What type of hydrogen atoms does heavy water contain?
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Compare the properties of heave water and ordinary water. See figure 12 page 112
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Next, we have the _______________ _______________of the atom. In the planetary model,
the nucleus is at the _______________and the electron’s move in _______________
_______________at fixed distances. Where did the planetary model come from?
_______________ _______________are the possible _______________that electrons in an
atom can have Bohr’s model is called the _______________ _______________because
_______________move with constant speed in fixed orbits around the nucleus, like planets
around the sun. Each electron has a certain amount of _______________. If an atom
_______________or _______________energy, the electron’s _______________also changes.
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Energy levels are kind of like a _______________.Taking one step is like moving up one
_______________level. You can only move in whole step increments, you can’t move a half a
step. In the same way, electrons can’t exist _______________energy levels.The bottom of the
staircase is like the _______________energy level in an atom.Each step up represents a
_______________energy level.An electron in an atom can move from one energy level to
another when the atom _______________or _______________energy.
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How do we know electrons can move from one energy level to another?Scientists can measure
the energy _______________when electrons absorb energy and move to a higher level, or the
energy _______________when the electron moves to a lower level. This _______________of
_______________explains the light seen when fireworks explode.
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Light is a form of _______________. The explosion of fireworks creates _______________which
causes some _______________to move to _______________energy levels. When these
electrons move back a to a _______________energy level, they _______________
_______________. Some of this energy is released as _______________
_______________.Different elements release different _______________of light because no
two _______________have the same _______________of _______________levels.
_______________was correct about energy levels, however, his assumption that
_______________move just like planets in a solar _______________wasn’t quite right.
_______________ (the likelihood or chance that something will or won’t happen) is required to
_______________the location/motion of an electron. In electron _______________is a visual
model of the most _______________location for electrons in an atom. The cloud is
_______________at locations where the probability is higher for the electron to be in that
place. Scientists use the electron cloud model to describe the possible locations of electrons
around the nucleus.
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The _______________cloud represents all the _______________in an atom. An
_______________is a region of _______________around the _______________where an
electron is likely to be. An _______________cloud is a good approximation of how electrons
behave in their orbitals. The _______________energy level has _______________orbital
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_______________energy levels have more. Each orbital can contain ______________electrons
at most . A _______________is an arrangement of objects in a given space. (kind of like the
configuration of our desks). An electron _______________is the arrangement of electrons in
the orbitals of an atom. The most _______________electron configuration is the one in which
the electrons are in orbitals with the _______________possible _______________.
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When all the electrons in an atom have the lowest possible energies, the atom is said to be in
it’s _______________state. Ex: lithium (atomic number 3) has 3 electrons. In ground state,
Lithium has 2 electrons in the first energy level, and the 3rd electrons is in the second energy
level. If Li absorbs energy, one electron may move to an orbital with a higher energy level. This
configuration is called an _______________state(which is less stable).