Atoms and elements


x] Everything around us is made up of very small particles called atoms.
x] Atoms can only be seen with an extremely powerful microscope
x] There are about 100 different types of atom. These are a few: oxygen, hydrogen, carbon, iron, tin, sulfur, silver, gold and platinum.
x] Some elements are solids, some are liquids and some are gases.

K = Potassium
Fe = Iron
Au = Gold
Ag = Silver
W = Tungsten
Hg = Mercury
H = Hydrogen
F = Fluorine
I = Iodine
B = Boron
S = Sulfur
O = Oxygen
Mg = Magnesium
Mn = Maganese

Word Equations

hydrogen + oxygen --> water
sodium + chlorine --> sodium chloride
carbon + oxygen --> carbon dioxide
copper + sulfur --> copper sulfide


Periodic Table

There are over 100 known elements. The elements in the periodic table are ordered in increasing atomic number.
image: modern periodic table
image: modern periodic table


Metals and non-metals

More than three quarters of the elements in the modern table are metals. They are mainly found in the two left-hand columns (Groups 1 and 2) and the central block (the transition metals). For your exam you need to be familiar with Group 1 and the transition metals.

Less than a quarter of the elements are non-metals, and are found on the right-hand side of the periodic table. For your exam you need to be familiar with Group 7 (the halogens) and Group 0 (noble gases).

Defenitions

Atom: the smallest particle of an element that retains all the chemical and physical properties of the element
Element: a substance made up of only one kind of atom.
Molecule: is composed of two or more atoms; a group of like or different atoms held together by chemical forces.
Particle: a very small piece or part.