2. Elements (review)

Elements There are just 92 types of elements. Everything on Earth and in space is made out of these atoms. All the elements are listed in the periodic table.

Names & Symbols of Elements There is a unique name and a symbol for each element. The name of the element is the same as its atom.

Periodic Table All the symbols and other information about all the elements can be found in a periodic table. They are put in order of atomic number.

The Periodic Table ↔ ↔ Rows are called periods. There are seven periods. Columns are called groups. Groups are numbered 1-18. Groups represent families Families shared common characteristics. ↔ ↔

Elemental Names

Inductive reasoning Use these examples to determine the IUPAC rules for writing chemical names correct wrong chlorine carbon dioxide oxygen sodium chloride calcium Iron HELIUM Neon Carbon Monoxide CHlorine

Use these examples to determine the rules for writing element symbols. Inductive reasoning Use these examples to determine the rules for writing element symbols. correct wrong Cl He I Mg Ca ar CL n FE hE

Practice ✔ or × hydrogen H Hydrogen h Einsteinium CL einsteinium Cl cl Names: Symbols: hydrogen Hydrogen Einsteinium einsteinium H h CL Cl cl

Special Elements In most samples of elements the atoms occur singly. These are called monatomic elements. In some elements in nature, their atoms are always bonded as pairs (they form molecules).These elements are called diatomic (di means two). In a few elements, their atoms are found in larger molecules. These elements are polyatomic. What does poly mean? He H2 Cl2 I2 P4 S8 helium hydrogen chlorine iodine phosphorus sulfur MONATOMIC DIATOMIC POLYATOMIC

Remembering the diatomics I Have No Bright Or Clever Friends is a mnemonic device to remember the 7 diatomic elements: I2, H2, N2, Br2, O2, Cl2, F2

The Periodic Table The periodic table is a special organization of elements by their atomic number (the number of protons). There have been many periodic tables developed, but the most popular one was developed by Dmitri Mendeleev. Mendeleev's periodic table effectively arranged atoms in a way that revealed many patterns in properties of atoms and allowed amazing predictions. Good science allows predictions.

Think Like Mendeleev In class activity

Pure Substances MATTER PURE SUBSTANCES IMPURE SUBSTANCES ELEMENTS COMPOUNDS METALS (Na, Ca, Fe, Ni) NONMETALS (S, He, F2, O2, N2)

Metals and Non-metals A simple way to classify elements zig-zag line or “staircase” NON-METALS METALS

Example metal families and properties Group 1 Alkali Metals Physical Properties lustrous malleable, ductile soft solids at room temperature excellent conductors of heat and electricity Chemical Properties reacts vigorously with water (not all metals do) reacts with oxygen reactivity increases down the periodic table. Group 2 Alkaline Earth Metals similar to Group 1 but slightly less reactive

Example nonmetal families and properties Nonmetal properties Periodic Videos Group 17 Halogens Group 18 - Noble Gases solids, liquids, or gases at standard temperature (250C) if solid they can be dull and brittle poor conductors of heat and electricity very chemically reactive with metals and oxygen gases at at standard temperature (250C) almost non-reactive; called inert chlorine bromine iodine

Periodic Table Colouring Activity

Patterns in the periodic table The organization of elements in the periodic table results in many other patterns. These include patterns in size and properties, boiling points, density and chemical reactivity. Atomic Size

Patterns in the periodic table Analysing graphs Worksheet