Chapter 2.1 Elements

Elements Element = pure substance that cannot be broken down into simpler substances. Elements are made of only one type of atom

Element Symbols Each element has a symbol, which is either one or two letters. The first letter is always capitalized. If there is a second letter, it is lower case. Some elements have symbols that don’t seem to make sense. This is because the symbol comes from the element’s Latin name. (Example: Mercury = Hg. Latin name = hydragyrum)

Elements Elements can be divided into two categories : Metals and Non-Metals Metals tend to be: Hard (at room temperature) Shiny Malleable (can be pounded into sheets) Ductile (can be stretched into wires) Good conductors of heat and electricity Non-metals tend to be: Gases or brittle (crumbly or breakable) solids at room temperature

Chapter 2.2 Periodic Table & Chemical Properties

The Periodic Table In the periodic table, elements are organized according to physical and chemical properties Each box of the periodic table lists information about the atoms that make up the element

Information on Periodic Table Name of the element Chemical symbol Atomic # = # of protons in the nucleus of each atom **The elements are arranged on the table according to their atomic number Average atomic mass = the weight of each atom Atomic mass – atomic # = # of neutrons Ion charge = electric charge of its atoms when they gain/lose electrons

Metals, Non-Metals and Metalloids Elements can be divided into three groups: metals, non-metals and metalloids Metalloids are elements that share properties with both the metals and the non-metals. Metals are found on the left, non-metals on the right and metalloids between the two Metalloids and non-metals form a zigzag staircase towards the right side

Periods and Families The periodic table has another pattern… Elements in a group (vertical column) have similar properties Elements in a group are often called a chemical family

Groups: Alkali Metals (group 1) Li, Na, K, Rb, Cs, Fr Highly reactive (reactivity increases as you go down the group) Low melting point Very soft metals Low density

Groups: Alkaline Earth Metals (group 2) Be, Mg, Ca, Sr, Ba, Ra Highly reactive (less than group 1 though) Fairly soft metals Low density

Groups: Halogens (group 17) F, Cl, Br, I, At Non-metals Highly reactive Gas at room temperature (except Br)

Groups: Noble Gases (group 18) He, Ne, Ar, Kr, Xe, Rn The most stable, unreactive elements Colourless, odourless gases )at room temperature)