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Dive into the world of atoms, metals, and elements with a detailed review of subatomic particles, atomic mass unit, transition metals, and more. Learn about the properties, reactivities, and locations of elements on the periodic table.
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Periodic Table Review Physical Science Chapter 5.3
Science Journal Entry #59 • Elaborate on the three subatomic particles in an atom. • Be sure to include charge and location in the atom.
Science Journal Entry #60 • Compare and contrast the halogens with the noble gasses stating location on the periodic table and reactivity as a minimum.
Atomic Mass Unit and Metals • Scientists needing a way to compare the masses of atoms, use the atomic mass unit (amu) which is defined as one twelfth the mass of a carbon-12 atom. • Recall that Metals are usually solid, shiny, good conductors of electric current or heat. Metals are malleable, (can be hammered without shattering), and ductile (can be drawn out into wire).
Transition Metals and Nonmetals • The metals in groups 3-12 are called transition metals because they form a bridge between the elements on the left and the elements on the right. Nonmetals are to the right of the table. They are not malleable or ductile and they do not conduct heat or electric current well. Fluorine is the most reactive nonmetal.
Metalloids • Metalloids are elements with properties that fall between metals and nonmetals. A metalloid’s ability to conduct electric current varies with temperature. • Across a period from left to right, the elements become less metallic and more nonmetallic in their properties. The most reactive metals are on the left side of the table. The most reactive nonmetals are on the right side in group 17.
Valence Electrons • A valence electron is an electron that is in the highest occupied energy level of an atom. They are the electrons on the outermost level from the nucleus. On the left are mainly metals, so why is hydrogen on that side of the table? The reason that hydrogen is on the left side although it is a nonmetal is due to its electron configuration.
Electron Configuration • All of the elements in group one have only one valence electron in their electron configuration. Elements in a group (other than hydrogen) have similar properties because they have the same number of valence electrons. • Group 1A (except hydrogen) are Alkali Metals. • The reactivity of alkali metals increases from the top of Group 1A to the bottom. • This group is colored red or pink in your paper periodic table.
Examples for Alkali Metals • Sodium (Na) is an alkali metal that can be cut with a knife since it is only as hard as cold butter. Sodium also has a low melting point of 98oC and has a lower density than water. • Sodium and potassium are stored under oil to keep them from reacting with oxygen and water vapor in the air. Cesium is usually stored in a sealed glass tube containing argon gas. Color red or pink.
Group 2 A: Alkaline Earth Metals • These metals are also very reactive and not found by themselves in nature. They have a much higher melting point than the alkali metals. Elements in Group 2A all have two valence electrons in their outermost energy level. Magnesium and calcium are used by our bodies. They are also used in construction and transportation. • Magnesium is in chlorophyll. It aids plants in photosynthesis. The frames of bicycles and backpacks often contain magnesium.
Examples of Alkaline Earth Metals Our bodies need calcium for strong bones and teeth. Calcium carbonate which is a compound of calcium, carbon, and oxygen is the main ingredient in chalk, limestone, coral, and the pearl. Other compounds of calcium are in toothpaste and plaster cast. Color this group blue.
Transition Metals • Groups 3-12 are the transition metals. They are not as reactive as groups one and two. Some give color to gemstones. The iron triad, that is iron, cobalt, and nickel are the only elements known to create a magnetic field.
Groups 11 • Native elements such as copper, silver, and gold are very un-reactive and can be found alone in nature and are called coinage metals. Copper wiring is an excellent conductor. Silver iodide and silver bromide are used in photographic film and paper. Color the coinage metals yellow.
Group 12 • Zinc and Cadmium is used in plating metals to protect them from the elements. Cadmium is in batteries that are re-chargeable. • Mercury, the only liquid metal at room temperature has been used in thermostats, switches, and batteries. It is toxic to living organisms and therefore has been closely monitored in food fish. Color zinc, cadmium and mercury purple.
Group 13 • Group 13 is called the Boron group. Boron is used in laundry products to soften water. Boron is a metalloid but the rest of the group are metals. • Aluminum is the most abundant metal in the Earth’s crust. Gallium, Indium, and Thallium are used as semiconductors. Color group 13 green.
Groups 14-16 • Groups 14 – 16 are named after the nonmetal at the top of the columns. The Carbon Group (14), the Nitrogen Group (15), and the Oxygen Group (16). These three nonmetals make up 86% of your body. Hydrogen, another nonmetal makes up 10% so nonmetals make up at least 96% of your body. • Color carbon, nitrogen and oxygen orange.
The Halogens • The elements in group 7A are called the halogens. They have 7 valence electrons in there outermost energy level. • Fluorine and chlorine are gases, bromine is a liquid that quickly evaporates away, and iodine is a solid that sublimes. Despite their physical differences, the halogens have similar chemical properties. Color 7A light blue.
Halogen Elements • Fluorine is the most reactive nonmetal and Chlorine is a close second. Fluorine is in toothpaste, and nonstick coating. Chlorine is in bleach, and is used to kill bacteria in swimming pools. • Your body needs iodine to keep its thyroid gland working properly. • Seafood is a good source of iodine. • At a time when fresh fish was not available, in all parts of the United States, iodine was added to salt. It was called iodized salt.
The Noble Gases • Group 8A is known as the noble gases. The noble gases have 8 valence electrons in their outermost energy level except helium that has two. • The noble gases are colorless, odorless, and are extremely nonreactive. All of the noble gases except Radon are used in “neon” lights. They are also used in laser light shows. • An argon atmosphere is used in the production of computer chips to prevent silicon from reacting with oxygen and nitrogen. Color light green.
Transuranium Elements • Elements past the atomic number 92 are called transuranium elements. Element 92 (uranium) is radioactive but natural. Those above 92 are synthetic, radioactive and very short lived. Half of the synthesized atoms disintegrate in about 2 days. Neptunium atoms form plutonium when they break down. Americium is used in smoke detectors.
