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.

Reactive Metals Transition Metals Rare Earth Metals Metalloids Halogens Noble Gases 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 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. Have properties of both metal and non-metal elements. Silicon is an example. Used to make semiconductors in electronic devices. Located in Group 17. Means forming salts. Very reactive non-metal. Often used to kill harmful micro-organisms. Chlorine and Iodine are good examples. 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.