S2 Vocabulary

Alpha Decay

• Release of a beta particle from the nucleus

• Release of a gamma ray from the nucleus

• Release of an alpha particle from the nucleus

• Release of a neutron from the nucleus

Atomic Theory

• the idea that matter is made up of fundamental particles called atoms

• the concept that energy cannot be created or destroyed

• the theory that all matter is composed of molecules

• the belief that atoms are indivisible and indestructible

Matter

• is anything that has mass and volume

• is a substance that can be seen and touched

• is a form of energy that can be converted

• is a concept that describes the absence of matter

Atom

• are the building blocks of matter

• are the smallest unit of a compound

• are made up of molecules

• are found only in solids

Half-life

• The time it takes for a substance to double in quantity

• The time it takes for half of an atom to decay

• The time it takes for a substance to reach its boiling point

• The time it takes for a substance to freeze

Intensive Properties

• Depends on the amount of matter present

• Does not depend on the amount of matter that is present

• Varies with temperature and pressure

• Is always equal to one

Mass

• a measure of the amount of matter

• a measure of the volume of an object

• a measure of the weight of an object

• a measure of the density of an object

Atomic Number

• The number of neutrons in an atom.

• The number of protons in an atom. It tells you what element it is.

• The total number of electrons in an atom.

• The mass of an atom measured in atomic mass units.

Chemical Properties

• Can be only observed by changing the composition/identity of the substance

• Can be observed without altering the substance

• Are the same as physical properties

• Are always visible to the naked eye

Protons

• neutral particle in the nucleus

• negative particle in the nucleus

• positive particle in the nucleus

• particle found in the electron cloud