Chapter 2.1: The Nature of Atoms Flashcards
Define atoms
• Atoms- the smallest unit of an element that contains all the characteristics of that element. Atoms are the building blocks of matter
Define matter
• Any substance in the universe that has mass and occupies space is defined as matter
Define atomic number
Different atoms are defined by the number of protons, quantity called the atomic number
Define element
An element is any substance that cannot be broken down to any other substance by ordinary chemical means
Define daltons
The mass of atoms and subatomic particles is measured in units called daltons
Define orbital
Orbital- a region around the nucleus of an atom with a high probability of containing an electron. The position of electrons can only be described by these probability distributions
Define cation
Cation- a positively charged ion
Define anion
Anion- a negatively charged ion
Define isotope
Isotope- different forms of the same element with the same number of protons but different numbers of neutrons
Define radioactive isotope
Radioactive Isotope- an isotope that is unstable and undergoes radioactive decay, releasing energy
Define half-life
half-life, the time it takes for one-half of the atoms in a sample to decay
Define energy level
o Energy Level- a discrete level, or quantum, of energy that an electron in an atom possesses
Define oxidation
o Oxidation- loss of an electron by an atom of molecule
Define reduction
o Reduction- gain of an electron by an atom or molecule
What is the smallest unit of an element that contains all the characteristics of that element?
atom
