Earth Science
Matter and its Changes
Merrill Chapter 2-1 Notes
2-1 Atoms

Matter-is anything that takes up space and has mass.
Examples:
1. Building blocks of matter are atoms.

Atoms:
1. Combine to form many different types of matter.
2. Elements are forms of matter that contain only one type of atom.
3. Examples of elements.
4. Structure: 3 primary particles
a. Protons-located in nucleus and has a positive electrical charge.
b. Neutrons-located in nucleus and has no electrical charge.
e. Electrons- located outside nucleus and has a negative electrical charge.
1. Electron Cloud

Mass Number of an atom: is the number of an atom is equal to the number of protons and neutrons making up its nucleus.

Atomic Number: equals the number of protons in its nucleus.
-If the number changes then a new element is formed.
-The number of neutrons can be changed without changing the element.

Merrill Chapter 2-2 Notes
2-2 Combinations of Atoms

Atoms combine in two ways:
1. By sharing electrons
2. By gaining or losing electrons they become positively or negatively charged.
a. Ion- electrically charged atoms.
b. Positive ions combine with negative ions.

Compound- a type of matter that has properties different from the properties of each of the elements in it.
Molecule-The smallest part of a compound.

Chemical Properties- describe how one substance changes when it reacts with other substances.

Mixtures- elements that are not chemically combined. EXAMPLES
1. Solution- special type of mixtures.

Chemical Change-converts one substance into one or more new substances.
Merrill Chapter 2-3 Notes
2-3 Matter

Physical Properties-properties or characteristics of a substance that can be observed and do not turn the substance into a new one.

Physical Properties
1. Density: is a measure of the mass of an objects divided by its volume.
Examples
2. States of Matter: 4 physical states or phases:
a. Solid- a definite shape and a definite volume: atoms closely packed together
b. Liquid- no definite shape and a definite volume: atoms further apart (greater
speed)
c. Gas- no definite shape and no definite volume (greatest speed no attractive force)
d. Plasma-matter in this state is composed of ions and electrons. Many electrons
in the state have escaped from their ions. Most abundant type of matter.

Changing states of matter:
The attraction between atoms or molecules and their rate of movement are two factors that determine the state of matter.

Changes in Physical Properties: Chemical properties of matter don't change when the matter changes state. Some physical properties do.

Think about Ice-Water-Water Vapor

Merrill Chapter 2-4Notes
2-4 Superconductors