Introduction to Chemistry Chemistry is the study of matter. Matter is anything that takes up space and has mass. All matter is made up of small particles called atoms. Atoms and elements are synonyms. F42ss8&feature=related F42ss8&feature=related

Atoms The atom is the basic unit of matter. Atoms are made of protons, electrons and neutrons. Atoms of different elements have different numbers of protons, neutrons and electrons

Elements There are currently 118 known elements. Atoms of all of these 118 elements are chemically combined to make every known substance. At room temperature most elements are solid, a few are gases and only mercury and bromine are liquids. All known types of atoms are found on the periodic table of the elements.

Data About an Element A periodic table usually shows each elements’ name, symbol, atomic number and atomic mass. Rules for naming chemical symbols: 1. Symbol always starts with a capital. 2. The second letter must be lowercase. 3. The symbol must be printed.

Why group elements? So that an element can be identified easily. Ex: Metals on the left, non-metals at the right except for hydrogen There are six major groups to learn

Metals All are solids except mercury Generally shiny and malleable Good conductors of heat & electricity

Alkali Metals Elements in Group I, except hydrogen Shiny, silvery Most reactive of all the metals

Non-metals Poor conductors of heat & electricity Many are gases at room temperature

Metalloids Are elements that possess both metallic & non-metallic properties. Are found along the step line of the periodic table.

Halogens Occupy the 17 th column Most reactive of non-metals and are usually found bonded to other atoms React with metals to form salts

Noble Gases Occupy the 18 th (far right) column All are gases at room temperature Extremely stable, unreactive

Elements can be in more than one group. Sodium is both a metal and an alkali metal. Neon is both a noble gas and a non-metal. wSKFBpo&feature=related wSKFBpo&feature=related Multiple Groups