More About The Periodic Table
In your science notebook, copy all Stop to Think questions and
Analysis questions. Provide a complete answer for each.
You will have 2 class periods to complete this lesson.
In this lesson you will need the copy of the periodic table handout you
were given earlier. As you go through the lesson, be sure to label the
location of each of the following:
Metals
Nonmetals
Metalloids
Noble Gases
Halogens
Transition Metals
Reactive Metals
Radioactive Elements
Key Vocabulary
Reactive
Likely to undergo a chemical change when combine with another material
Metal
An element that tend to be shiny, easily shaped and a good conductor of electricity and heat.
Nonmetal
An element that is not a metal and has properties generally the opposite of those of metal.
Metalloid
An element that has properties of both metals and non-metals
Isotopes
Isotopes are atoms with the same number of protons , but differing numbers of neutrons.
Isotopes are different forms of a single element
Radioactivity
The process by which the nucleus of an atom of an element releases energy and particles.
Half-life
The length of time it takes for half of the atoms in a sample of radioactive element to decay
into atoms of another element.
In your science notebook, make a copy of the table below. As you read through the lesson,
make notes about each of the following. Consider how each is used, provide examples, and
any other information you feel is note worthy
Reactive Metals
Transition Metals
Rare Earth Metals
Can undergo chemical changes. Elements in Group 1 very reactive. Sodium and
Potassium are examples. Elements in Group 2 are less reactive than Group 1.
Group 18 are the least reactive of all elements.
Groups 3 – 12. Some of the earliest known metals. Copper, Gold, Silver, Iron.
Can be combined to make alloy. Good conductor of heat and electricity. Less
reactive than alkali metals.
Located at the top level of bottom rows. However some periodic table consider
both rows to be rare earth metals. Referred to as Lanthanum (top row) and
Actinide (bottom row). Called rare earth metals because was once believed hard
to find.
Metalloids
Have properties of both metal and non-metal elements. Silicon is an example.
Used to make semiconductors in electronic devices.
Halogens
Located in Group 17. Means forming salts. Very reactive non-metal. Often used
to kill harmful micro-organisms. Chlorine and Iodine are good examples.
Noble Gases
Located in Group 18. Almost never react with other elements. Can be located
in atmosphere. Used to make light. Radon is radioactive but can be used to
treat some cancers
Stop to Think
Elements with similar properties are located near each
other in the periodic table.
Stop to Think
Explain why the Lanthanum elements are considered Rare Earth Metals
It was once believed that these elements only existed in tiny
amounts and were difficult to locate due to poor mining
technologies.
Note: Other periodic tables will identify both lower rows as rare
earth metals.
Stop to Think
Many of the noble gases can be found in the
Earth’s atmosphere.
What is an Isotope?
An isotope is one particular form an atom that an element might take. Just as people may be
thin, medium weight, or heavy, isotopes vary according to their weight.
You will remember from the last chapter that the mass of an atom is determined by adding the
number of protons to the number of neutrons in the nucleus. Since all the atoms of an element
must have the same number of protons, the only thing that can vary to cause this change is the
number of neutrons.
Put simply: Isotopes are atoms with the same number of protons , but differing numbers of
neutrons . Isotopes are different forms of a single element .
Examples: Carbon 12 and Carbon 14 are both isotopes of carbon , one with 6 neutrons and
one with 8 neutrons (both with 6 protons ).
Click the link below and closely listen to how the scientist explains the definition of an isotope
and how isotopes change the weight of an element, but do not affect the other properties of
an element.
What is an Isotope?
Stop to Think
The stability of an atom depends on the correct balance of protons and neutrons. This
balance is what holds the nucleus together. If there is are to few or too many neutrons
(making it an isotope) the atom becomes unbalanced. When this occurs, particles are
produce inside the nucleus to restore the proper balance, therefore changing the nucleus.
In short, radioactive decay causes the number of protons in the nucleus to change.
Click the link below to better understand how radioactive
decay is used in science, especially in determine how old
something is:
Radioactive Decay
Analysis
Copy each of the following question and provide a complete answer.
The 3 major classes of elements are metals, metalloids,
and non-metals.
Some characteristics of metals can be that they are shiny,
easily shaped or bent, make good conductors of heat and
electricity.
An atom of one element can change into an atom of
another element though radioactive decay which
causes the number of protons in the nucleus to
change.
The short answer is Fluorine. But this is why: both
Carbon and Fluorine are in period two. When you go
across the period, the number of protons increase and
the charge is getting stronger. This also has to do with
valences and electrons, but we’ll get to that.