Mid Year Science Review

Chemistry, Earth History, Infectious Diseases

Groups and Periods

Groups are the numbers that is above the periodic table. The groups are vertical.

Periods are the numbers beside the periodic table. Periods are horizontal.

Law of Conservation of Mass

The law of conservation states that matter cannot be created nor destroyed, it can only be transferred from state to state.


are a pure substance made up of only one type of atom and cannot be separated into simpler substances.


Compounds are combination of elements that cannot be physically separated.


is a combination of two or more substances that are not chemically bonded and be separated by physical means

Physical Properties

Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter. Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.

Chemical Properties

A chemical property is any of a materials properties that becomes evident during a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity.

Physical changes

A physical change is any change NOT involving a change in the substance's chemical identity. Here are some examples: (1) any phase change. Moving between solid, liquid and gas involves only the amount of energy in the sample

Chemical changes

Chemical change is any change that results in the formation of new chemical substances. At the molecular level, chemical change involves making or breaking of bonds between atoms. These changes are chemical: iron rusting


  • Periodic Table
  • Atomic Number
  • Atomic Mass
  • Groups
  • Periods
  • Law of Conservation of Mass
  • Element
  • Compound
  • Mixtures
  • Physical Properties
  • Chemical Properties
  • Physical Changes
  • Chemical Changes