Lesson 2 Matter

All matter consists of particles called atoms. The following is a list of the basic characteristics of atoms and how this information is related to the organization of the periodic table.

• Atoms consist of a nucleus, which contains protons and neutrons (together these particles are called nucleons), and electrons, which are located in a cloud outside of the nucleus.
• An electron can potentially be found at any distance from the nucleus, but depending on its energy level, they exist more frequently in certain regions around the nucleus than others; this pattern is referred to as the atomic orbital. The orbitals come in a variety of shapes (these shapes are beyond the scope of Science 10).
• Each electron has a negative charge and is 1/1 840 the size of a proton or neutron.
• Protons and neutrons are about the same size.
• Each neutron is neutral.
• Each proton has a positive charge.
• The number of protons (also known as its atomic number) determines the element.
• Varying the number of neutrons results in isotopes. Isotopes are variations of a single element.
• Elements are arranged in order of increasing atomic number on the periodic table. This arrangement leads to patterns on the periodic table, such as period number representing the number of energy levels and the last digit of the group number representing the number of valence electrons.
• Elements in groups or families have similar chemical properties.

ChemThink Atomic Structure Tutorial @ Simbucket/PBS https://quick.adlc.ca/chemthink3

Work through this online tutorial to review the structure of the atom and subatomic particles.