Essay Marriage: Atom and Valence Electrons

Submitted By samojan
Words: 905
Pages: 4

Is also called thermal energy.
Is associated with the motion of particles.

Matter – anything that has mass and takes up space or occupied space (EVERYTHING!!!!!)

Mixtures are
Classified by their composition.
Called homogeneous when they are uniform (Solution)
Called heterogeneous when they are not uniform.
In a homogeneous mixture, the composition is uniform throughout, and different parts of the mixture are not visible.
In a heterogeneous mixture, the composition is not uniform; it varies from one part of the mixture to another, and different parts of the mixture are visible.
State of matter: solid, liquids and gases

Solids a state of matter that takes up the shape of its container but has a definite volume

Liquids a state of matter that takes up the shape of its container but has a definite volume.

Gases: A state of matter characterized by no definite shape or volume. Particles in a gas move rapidly

Density: relationship of the mass of an object to its volume expressed as grams per cubic centimeter……
Is the mass of a substance divided by its volume.
Are measured in g/L for gases.
Are measured in g/cm3 or g/mL for solids and liquids.

Elements are pure substances that contain atoms of only one type.
Copper (Cu) Lead (Pb) Aluminum (Al)
Elements are pure substances from which all other things are built.

A physical change

physical change: the change in which the physical appearance of a substance changes , but the chemical composition stays the same. Chemical change

A chemical change occurs when one or more substance react to form a substance with new physical and chemical properties.


Group 7A (17), the halogens, includes fluorine, chlorine, bromine, iodine, and astatine. Fluorine and chlorine are highly reactive.

Noble gases:

Group 8A (18) is the nobel gases, which include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Ra).
Nobel gas elements are unreactive and are seldom found in combination with other elements.

Metals, Nonmetals, and Metalloids
The heavy zigzag line separates metals and nonmetals. Metals (blue) are located to the left.
Nonmetals (yellow) are located to the right.
Metalloids (green) are located along the heavy zigzag line between the metals and nonmetals.

Metals are
Shiny and ductile. good conductors of heat and electricity.
Nonmetals are
Not especially shiny, ductile, or malleable.
Poor conductors of heat and electricity.
Metalloids are
Better conductors than nonmetals, but not as good as metals. used as semiconductors and insulators.

Atoms are tiny particles of matter too small to see, are able to combine with other atoms to make compounds, and are similar to each other for each element and different from atoms of other elements.

Atoms contain subatomic Particles such as
Protons, which have a positive (+) charge; ( P=atomic #)
Electrons, which have a negative (–) charge; and
Neutrons, which have no charge. (N=mass number-atomic number)
Experiments show that like
Charges repel and unlike
Charges attract.

The atomic number

A number that is equal to number of protons in an atom

Atomic number-----11


Number of protons + number of neutrons.

Potential energy is the energy stored for use at a later time. is determined by the position of an object or by the chemical composition of a substance
An energy associated with forces of attraction or repulsion between objects
water behind a dam a compressed spring chemical bonds in .gasoline, coal, or food

Kinetic energy is the energy of matter in motion.
swimming water flowing over a dam working out burning gasoline

Isotopes are atoms of the same element that have different mass numbers. have the same number of protons but