Properties of Non-metals
Your Body ► Most of your body’s mass is made of oxygen, carbon, hydrogen, and nitrogen. ► Calcium, a metal, and other elements make up the remaining 4% of your body’s mass. ► Many of the elements found in your body are classified as non-metals. Non-metals are elements that usually are gases or brittle solids at room temperature.
Non-metal Properties ► Because solid non-metals are brittle or powdery, they are not malleable or ductile. (What does that mean?) (what are those characteristics of?) ► Most non-metals do not conduct heat or electricity well, and generally they are not shiny. (they are dull)
The one exception ► In the periodic table, all non-metals except hydrogen are found at the right of the stair- step line.
Bonding in Non-metals ► The electrons in most non-metals are strongly attracted to the nucleus of the atom. (not to be confused with the “looseness of metals”) So, as a group, nonmetals are poor conductors of heat and electricity. ► Most nonmetals can form Ionic and covalent compounds.
Examples ► Pb S (How many valence electrons for each?) ► S Pb S - Ionic bond ► Metal and nonmental
Example ► CO 2 ► Draw the dot diagram O C O O C O O C O - Covalent bond O C O - Covalent bond nonmetal and nonmetal
Covalent Bonding ► When nonmetals bond they usually share (everything I learned in kindergarten) electrons to form compounds. ► This is covalent bonding. - Sharing
Hydrogen ► 90% of the Universe is made of Hydrogen Most hydrogen on Earth is found in the compound water. Hydrogen means water forming When water is broken down into its elements, hydrogen becomes a gas made up of a diatomic molecule.
Diatomic Molecule ► Diatomic Molecule consists of 2 atoms of the same element in a covalent bond. ► H 2 O 2 N 2 F 2
The Halogens ► Group 17 ► They are very reactive in their elemental form, and their compounds have many uses. ► Fluoride is added to toothpaste to prevent tooth decay. ► Chorine is added to water to disinfect it. ► Halogens have 7 valence electrons in their outer shell, thus only needing one electron to complete it.
Very Important ► If a halogen gains an electron from a metal in group 1, then an ionic compound is formed. ► It’s called a salt. ► Example: NaCl – table salt
Color of Halogens ► In their gaseous state, halogens can be identified by their color. ► Chlorine: greenish yellow ► Bromine: reddish orange ► Iodine: Violet
Uses of Halogens ► Chlorine is used in pools to disinfect it. ► Bromine is used as a red dye. ► Iodine is essential to our diets for the production of the hormone Thyroxin.
Sublimation ► Sublimation – is the process of a solid changing directly to a vapor without forming a liquid. ► Ex. Dry Ice – Frozen CO 2
The Noble Gases ► The noble gases exist as isolated atoms. They are stable because their outermost energy levels are full. ► The stability of noble gases is what makes them useful.