20 terms

Unit 1: Atoms

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Matter
Anything with mass and volume
Atomic Name
The name of an atom (ex: Helium, Sulfur)
Physical Property
A characteristic of a substance that can be changed without permanently altering the substance
Chemical Property
A characteristic of a substance that determines how it will interact with other substances
Mass
The amount of matter in an object
Atom
The smallest unit of matter (always neutral in charge with the same # of protons and electrons)
Atomic Mass
The mass of a single atom of an element (protons+neutrons)
Atomic Number
The number of protons in an atom (NEVER changes)
Atomic Symbol
The letter(s) that represent an atom on the Periodic Table (1st= ALWAYS capital, 2nd= ALWAYS little)
Electrical Charge
The positive or negative charge of a subatomic particle
Nucleus
The "core" or middle of an atom (contains the protons and neutrons)
Electron Cloud
The area or "cloud" around the nucleus where electrons are found
Energy Levels
Specific regions within the electron cloud, larger atoms = more levels (up to 7)
Subatomic Particles
All 3 particles that make up atoms
Proton
A positively charged particle located in the nucleus; the number NEVER changes; identifies the element
Neutron
A neutral particle located in the nucleus; atoms with a different # than usual is called an isotope
Electron
A negatively charged particle located in the electron cloud; atoms with a different # than usual is an ion
Valence Electrons
The electrons found in the outermost energy level
Isotope
An atom with more or less neutrons than the variety shown on the periodic table
Ion
An atom with more or less electrons than protons (has a positive or negative charge)