Classifying Elements Atomic Number Symbol Atomic Mass Periodic Table Metals Nonmetals Alloys Noble Gases

What are symbols? One or two letters that represent the name of an element. All of the symbols have either one or two letters. The first letter of each symbol is a capital letter, and the second letter is a small letter. No period is used at the end of a symbol.

What is the Periodic Table?

Terms to Know Isotopes-one of a group of atoms of an element with the same number of protons but different numbers of neutrons. Deuterium-an isotope of hydrogen that has one proton and one neutron. Tritium-an isotope of hydrogen that has one proton and two neutrons. Atomic mass-the average mass of all the isotopes of a particular element.

Continued terms Family-a group of elements with similar properties,arranged together in a column of the periodic table Metal-one of a group of elements that is usually solid at room temperature, often shiny, and carries heat and electricity well. Alloy-a mixture of two or more metals. Nonmetal-a group of elements with properties opposite to those of metals.

Metal Facts Most metals are solid at room temperature. Most metals can be polished to look shiny. The shape of a metal can be changed. For example, aluminum can be pounded into a thin foil without being broken. Copper is often stretched into very thin wires. Electricity and heat travel well through metals.

Nobel Gases One of a group of elements made up of gases that do not combine with other materials under ordinary conditions. Neon is an example of a noble gas. Inert- a description of an element whose atoms do not react in nature with atoms of other elements.

Alkali - group 1 Metals/Very reactive most reactive metals Have only 1 electron in outer level Low density

Alkaline-Earth (group 2) Metals/Very reactive (but less than alkali) have 2 outer level electrons Higher density than alkali

Transition Group 3-12 Metals/ Tend to be shiny Tend to conduct thermal energy and electric current well

Carbon Nonmetal several natural forms (diamond/soot) No life can exist without carbon Living things, proteins, fats, etc.

Oxygen 20% of air you breathe

Noble Gases Light bulbs

Hydrogen Properties don’t match the properties of any single group Colorless odorless gas

Periodic law States that chemical and physical properties of elements are periodic functions of the elements atomic numbers. This is WHY?! – Elements in vertical groups share similar properties