Unit 4 - Bonded Particles - Electrical Nature of Matter

Particle representations of matter as pure substances and mixtures. Pure substances are further subdivided into elements and compounds



The particles that make up substances can be compounded from smaller particles.
The fact that compounds have definite composition leads us to Dalton’s model of the atom. Next we find that these smaller particles (atoms) have the property of charge and some internal structure; we use the Thomson model of the atom to account for our observations.

Matter is composed or pure substances or mixtures of these pure substances. The molecules of pure substances have definite composition and properties whereas the composition and properties of mixtures are variable.
Molecules of pure substances can be broken down into simpler particles (atoms or molecules).

The energy required to separate the atoms in a compound is greater than that required to separate molecules during a phase change.

Two kinds of charge are observed to exist in atoms. The mobility of charge within and between atoms suggests atoms are composed of smaller particles with opposite charge properties. Charge plays a role in the attractive forces that hold solids and liquids together and binds the atoms in molecules or crystal lattices.
Molecular substances are composed of neutral molecules, whereas ionic substances are lattice-work structures of ions. These two kinds of substance have different physical properties.


Dr. Michael M. Krop High School







Unit 4 Materials


m r . m o n t e r o . c o m





Like charges on individual hairs make them repel each other and stand away from this man's head. How did the hairs become charged? What is the role of the metal object he is touching?