Arrangement of the Periodic Table
Driving Question: How is the periodic table of elements arranged?
WOW! Look at all these pieces we have to put together! How in the world will we ever be able to arrange them? Take your best shot!
This puzzle was 81 pieces! Imagine if you had to sort and arrange more than that? How would you do it? Let's look into how some people from history have sorted a group this big!
Question Mark Image
Watch this video and explore the genius that went into organizing the periodic table.
Okay, Let's dissect the periodic table.
Elements on the periodic table are arranged by the way that they behave. The periodic table is one of the most useful tools to a chemist. Based on an elements position on the periodic table, one can infer a wealth of information about that element's properties.
Parts of the Periodic Table
- Groups/Families (1-18) - vertical columns (up & down)
- The groups colored below are the the Representative or Main Group Elements. These are the elements for which there is a periodic repetition of their properties. The pattern repeats every 8 elements.
- Elements in the same group have the same number of valence electrons and, therefore, have similar properties.
- Periods (7) - horizontal rows
- Elements in the same period have the same number of energy levels of electrons.
- There are 7 periods on the periodic table. Those two at the bottom actually belong in periods 6 and 7, hence the coloration.
- Transition elements (groups 3-12)
- Elements in this section of the periodic table can have some complicated electron arrangements.
- They do exhibit some common properties, however. Most are shiny, good conductors, and many can be found freely in nature (copper, gold, siver).
Spanning the periodic table are three categories of elements: metals, nonmetals and metalloids.
- Metals - left of the zig zag line
- Shiny/Luster when smooth and clean
- Solids at room temperature (exc: mercury, Hg)
- Good conductors of heat and electricity
- Ductile (drawn into wire) & Malleable (bendable)
- Metalloids - along zig zag line; have properties of both metals and nonmetals
- Nonmetals - right of zig zag line; generally gases or brittle, dull solids (exc: bromine, Br)
Let's look even closer...
Elements on the periodic table are grouped so that elements in the same column have similar chemical and physical properties. This relationship exists because elements in the same group have the same number of valence electrons. Let's look at the properties of each group:
—Group 1: Alkali Metals (excluding hydrogen)
- Elements in this group have 1 valence electron.
- They tend to give away this electron and form cations with a +1 charge.
- These metals are extremely reactive. They will react with water vapor in the air and, therefore, must be stored in oil or inert gases. For this reason, they are never found freely in nature.
- Alakali metals are soft, silvery metals that can be cut with a knife.
—Group 2: Alkaline-earth Metals
- Elements in this group have 2 valence electrons.
- They tend to give away these 2 electrons and form cations with a +2 charge.
- Alkaline-earth metals are reactive, but not to the extent of alkali metals. They can be found in nature freely, but are more often found in compounds.
- They are often mixed with other metals to make low density materials like airplanes, ladders, etc.
—Groups 3-12: Transition Metals
- Elements in this region can have 0, 1, or 2 valence electrons -- there is no real pattern.
- They do give away their valence electrons and can form cations with charges anywhere from +1 to +7.
- However, these elements don't give away their valence electrons as easily as alkali or alkaline earth metals, so they are not as reactive. They are frequently found free in nature.
Inner Transition Metals
- Lanthanides and Actinides are some transition metals from Periods 6 & 7 and are placed at the bottom of the periodic table.
- Elements from these series are also known as rare earth elements.
- Lanthanides can be used in superconductors, glass production, or lasers.
- Actinides are all radioactive, and some are not found in nature; many are synthetic and have only been made in laboratories using particle accelerators.
Groups 13-16: Groups with Metalloids
Elements in these groups are a mixture of metals, nonmetals, and metalloids and, therefore, have a mixture of properties.
Group 13: Boron Group - have 3 valence electrons and typically form cations with a +3 charge
Group 14: Carbon Group - have 4 valence electrons; tin and lead at the bottom of the group can form ions with a +2 or +4 charge, but carbon most often does not form ions
Group 15: Nitrogen Group - have 5 valence electrons and typically form anions with a -3 charge (They need to gain 3 extra electrons to complete their valence shell.)
Group 16: Oxygen Group - have 6 valence electrons and typically form anions with a -2 charge
Group 17: Halogens
- Elements in this group have 7 valence electrons.
- They are 1 electron away from that magical numer of 8 valence electrons. They typically gain 1 extra electron and form anions with a -1 charge.
- All elements in this group are nonmetals.
- Most are gases, with the exception of bromine -- a liquid.
- These nonmetals react readily with alkali metals to form stable ionic compounds, or salts.
Group 18: Noble Gases
- Elements in this group have 8 valence shell electrons.
- Because their valence shell is complete, they typically do not lost, gain, or share electrons, and they do not form ions. THEY ARE STABLE AND UNREACTIVE!!!
- These were some of the last elements to be discovered, because they are just unreactive.
- Obviously, elements in this group are all nonmetallic gases. Many are used in neon signs, to fill balloons, and as insulation between glass window panes.
An Element in a Group of its Own: Hydrogen
- Hydrogen has 1 valence electron, so it is often placed in group 1. It can lose that electron and form a cation with a +1 charge.
- However, it can also gain one electron and form an anion with a -1 charge.
- Because it can behave chemically like a metal (lose valence electrons) or a nonmetal (gain valence electrons), it is considered in a group of its own.
- Hydrogen is a colorless, odorless gas. It is very flammable, and it is the most abundant element in the universe!!!
As you can see, there is a wealth of information about the elements on the periodic table. Make sure that you can identify the various regions and groups on the periodic table. Also, be able to identify how many valence electrons and the charge formed by elements in each group.
Explore a Periodic Table and fill in the crossword with the element that the clue is describing. Before you start, you will want to have a Periodic Table handy to look at: Open this Interactive Periodic Table in a new window so you can flip back and forth to complete the crossword.
Activity adapted from web site
This lesson contains a LOT of information. Make sure that you have taken extensive notes and are quite familiar with the arrangment of the periodic table.
Can you answer today's question?
How is the Periodic Table of Elements arranged?
Items to be Submitted
1. Read, take notes, study, and work to memorize the ideas about how the Periodic Table is arranged.
2. Spend a little time working on your Science Fair Proposal that is due soon!