Presentation on theme: "Nonmetals & Metalloids. Nonmetals Nonmetals are located to the right of the stair step line on the periodic table except for hydrogen Nonmetals are usually."— Presentation transcript:
Nonmetals & Metalloids
Nonmetals Nonmetals are located to the right of the stair step line on the periodic table except for hydrogen Nonmetals are usually gases or brittle solids Nonmetals are poor conductors of heat and electricity because the outer electrons are strongly attracted to the nucleus
Hydrogen It is an exception to location on the periodic table because it shares chemical properties with the alkali metals 90 percent of all atoms in the universe are hydrogen Hydrogen is highly reactive Hydrogen can be found as a diatomic molecule, or two molecules of the same type joined together
Halogens – Group 17 Halogens are very reactive in their elemental form and are only found in nature in compounds They contain seven electrons in their outer energy level In their gaseous state, halogens form diatomic molecules of distinctive colors: Chlorine – greenish yellow, Bromine – reddish orange, Iodine - violet Fluorine is the most chemically active element Bromine is the only nonmetal that is a liquid at room temperature
Uses of Halogens Halogens are used in halogen lamp bulbs to give them a longer life Chlorine and bromine compounds are used to disinfect drinking water or pool water Fluoride compounds are used in toothpaste to prevent tooth decay. Iodine is essential to you diet for the production of the hormone thyroxin.
The Noble Gases The noble gases exist as isolated atoms They are the most stable elements because their outer energy levels are filled There are no naturally occurring noble gas compounds, but compounds of xenon and krypton with fluorine have been created in laboratories.
Uses of Noble Gases Their inability to react is what makes noble gases useful They are used as components of high performance lightbulbs and neon lighting High powered lasers used in light shows or for medical purposes use noble gases. Helium is used in blimps and balloons due to it’s low density
Metalloids Metalloids are the elements that border the stair step on the periodic table except for aluminum and polonium They have properties of both metals and nonmetals Metalloids are also known as semiconductors due to the fact that they can conduct heat and electricity under certain conditions They are usually metallic looking solids that are brittle
Uses of Metalloids The most common use of metalloids is in electronics in the form of semiconductors or microchips They are also used to form alloys with metals to enhance their properties
Mixed Groups The remaining groups on the periodic table are all mixed groups, they contain metals, nonmetals, and metalloids They have similar chemical properties but dissimilar physical properties
Some Important Nonmetals Carbon is important to all life on Earth Silicon is the second most abundant element in the Earth’s crust after oxygen Silicon and Carbon both occur in different allotropes – different forms of the same element
Some Important Nonmetals Nitrogen is the main component of the air we breath Nitrogen and Phosphorus are used to make fertilizers They are also the components of many organic compounds including DNA Phosphorus is also used to make matches, and certain forms of it glow when exposed to oxygen Oxygen is used by most life on Earth for respiration and exists in the air as diatomic molecules
Synthetic Elements Not all elements found on the periodic table are found naturally Some elements are found only by creating them in a laboratory With the exception of technetium and promethium, all synthetic elements have a 93 or more protons. These elements are created by smashing existing elements together in a particle accelerator
Transuranium Elements All elements on the periodic table with 93 or more protons are called transuranium elements and are synthetically created All are unstable, and many disintegrate quickly It is theorized that stable synthetic elements may exist that can overcome the enormous repulsion forces of the protons