Download Chapter 4.3: How Atoms Differ

The Structure of
an Atom
Chapter 4.3: How Atoms Differ
Atomic Number
✦
Main Idea: The number of _______ and ______
number define the _____ of ______.
✦
Just like people and objects can be identified by
_____________ (ie~ SSN or IP address), ________
and __________ are also _________ by numbers.
Atomic Number
✦
Henry Moseley
✦
Discovered atoms of each _________ contain a
unique _________ charge in their ____________.
✦
✦
Number of ____________ identifies an _______ as
part of a particular ___________.
Referred to as ___________ ______________.
4.3 How Atoms differ
Atomic Number
Main Idea: The number of protons and
✦
✦
Periodic table organized by
____________ atomic number.
Atomic number
Atomic number = number of
____________ in an atom.
✦
✦
Number of protons = number of
_______________
All atoms are ________________.
Isotopes -
Mass Number -
Isotopes & Mass Number
✦
Dalton stated that atoms were not divisible and that all
atoms of an element had to be identical.
✦
✦
Atoms have the same number of ___________ and
_______________.
✦
✦
Was he correct?
Number of _____________ might differ.
Atoms with same number of ___________ but
different numbers of __________ = _______________.
Isotopes & Mass Number
Isotope notation -
✦
Isotopes of element
identified by _________
_________________.
✦
______ of the _________
number and __________
in the nucleus.
✦
✦
_______ _________ =
# protons + # neutrons
Mass of atoms
Most elements found as
Atomic Mass Unit (amu) ________ of __________.
Mass of Atoms
✦
____________ particles have small _____________.
ss of atoms
✦
Developed method of measuring ______ relative to ________.
mic Mass Unit (amu) ✦
✦
____________ atom = 12 __________ ________ _________
One atomic mass unit (amu) = _______ the mass of a
carbon-12 atom.
Mass of Atoms
✦
Atomic mass = the ___________ ___________ mass of
the _____________ of an element.
✦
________
Average
Atomic
Massa- whole
number.
✦
Isotopes have different ________.
✦
Isotopes found in different relative ______________.
Mass of Atoms
Practice Problems:
Boron has two naturally occurring isotopes: boron-10 (abundance = 19.8%), mass =
Given the
data
in boron-11
the table,(abundance
calculate the= atomic
unknown
X.
10.013
amu)
and
80.2%,mass
massof=an
11.009
amu).Element
Calculate
Then
identifyatomic
the unknown
the
average
mass orelement,
boron. which is used medically to treat some mental
disorders.
Isotope
Mass (amu)
Percent Abundance
6
X
6.015
7.59%
77
X
7.016
92.41%
Mass of Atoms
Practice Problems:
Given the data in the table, calculate the atomic mass of an unknown Element X.
Then identify the unknown element, which is used medically to treat some mental
disorders.
Isotope
Mass (amu)
Percent Abundance
6
X
6.015
7.59%
7
X
7.016
92.41%
Mass of Atoms
Practice Problems:
Nitrogen
has
two
naturally
occurring
isotopes,
N-14
&
N-15.
Its
Given the data in the table, calculate the atomic mass of an unknown Element X.
atomic
mass
14.007.element,
Which
isotope
more abundant?
Then
identify
theisunknown
which
is usedismedically
to treat some mental
disorders.
Isotope
Mass (amu)
Percent Abundance
6
X
6.015
7.59%
7
X
7.016
92.41%
The Structure of
an Atom
Chapter 4.4: Unstable Nuclei &
Radioactive Decay
Unstable Nuclei &
Radioactive Decay
✦
Main Idea: __________ atoms emit _____________
to gain ____________.
✦
✦
Review: What happens in a chemical reaction?
New type of reaction can _________ one element into
a ________ element.
✦
___________ ____________
Unstable Nuclei &
Radioactive Decay
Radioactivity
✦
_________________ is the process of substances
________________ emitting _______________.
✦
✦
Radiation = The _________ and ______________
emitted by ______________ materials.
Radioactive atoms undergo _____________ that can
alter their ___________ through __________
reactions.
✦
Changes an atom’s _____________.
✦
Emit radiation because their _______ are ____________.
Radioactivity
✦
Spontaneous process of ____________ nuclei emitting
___________ is called ______________ ___________.
✦
✦
Nuclei ___________ __________ during this process.
Undergo radioactive decay until they form _______
__________.
✦
Usually results in a ________ element.
Types of Radiation
✦
✦
Scientists identified ________ different types of
radiation by directing _____________ between two
______________ charged plates.
Identification based upon _______ ______ of particle.
Types of Radiation
✦
Alpha Radiation
✦
Deflected toward the ___________ plate.
✦
Made up of _________ particles.
✦
Contains ______ protons and _______ neutrons.
✦
Has _____ charge & equal to a _________ nucleus.
✦
Represented by: __________ or the symbol ____
Types of Radiation
✦
Alpha Radiation
✦
Type of equation = ______________ ________________.
✦
Radioactive radium changes to stable radon
✦
Notice that __________ __________ is ____________ in this reaction.
Types of Radiation
✦
Beta Radiation
✦
Deflected toward the _____________ plate.
✦
Made up of fast-moving _________ particles.
✦
Same as an ___________.
✦
Has ________ charge.
✦
Represented by: __________ or the symbol ____
Types of Radiation
✦
Beta Radiation
✦
Type of equation = nuclear equation.
✦
Radioactive iodine changes to xenon radon
✦
Notice that mass number is conserved in this reaction.
Types of Radiation
✦
Gamma Radiation (Rays)
✦
_______ __________ radiation that does not have
__________.
✦
✦
Charge is ___________.
✦
✦
Represented by the symbol ____
______ ____________ by electric or magnetic fields.
Account for ________ of the _________ lost
during radioactive _____________.
Types of Radiation
Gamma Decay -
Radioactive Decay
Practice Problems:
Write the equation for the alpha decay of Bismuth-214.
Write the equation for the beta decay of Neptunium-239
Nuclear Stability
Radioactive Decay
When writing radioactive decomposition reactions, the mass numbers (top) and the atomic numbers
(bottom) must be equal on both sides.
Radioactivity Problems – write the equations for the following radioactive decomposition reactions
1.
alpha decay of uranium – 238
2.
beta decay of phosphorus – 32
3.
alpha decay of carbon – 14
4.
alpha decay of potassium – 40
5.
beta decay of argon – 37