Elements, Atoms, Molecules & Compounds

Elements An element is a simple substance that cannot be broken down Ex: Iron, Mercury, Oxygen More than 100 elements Can be solid, liquid or gas at room temp. (most are solid) Iron = Solid Mercury = Liquid Oxygen = Gas

Periodic Table of Elements

Atoms An atom is the smallest part of an element that can be recognized as the element ***** Made up of three particles: Neutrons: neutral charge (0) Protons: positive charge (+) Electrons: negative charge (-) Atoms have no overall charge because each one has the same number of protons and electrons Atoms are too small to see with our eyes Millions of atoms could fit on the period at the end of this sentence.

Protons and neutrons are found in the center, or nucleus, of the atom Electrons are spread out around the nucleus in locations called “shells” or “energy levels” The electrons found in the outermost shell are called valence electrons Each shell can hold a specific number of electrons (2, 8, 18, 32, 32, 18, 8)

How many protons are there? Neutrons? Electrons? An Example of an Atom + + + + How many protons are there? Neutrons? Electrons?

Molecules A molecule is at least two atoms that are bonded (stuck) together Can be the same or different elements Think of it as a string of atoms

Compounds A substance that is made of two or more elements bonded together Must have at least two elements Ex: Water (H2O) Oxygen Hydrogen

Water is actually a molecule and a compound. It is made of at least two atoms bonded together. Those atoms are made of two different elements. Oxygen Hydrogen

Matter Atoms make up matter Matter makes up EVERYTHING Matter is anything that has mass and volume Examples include: The planet Earth You Your pen A rubber band