Biology Chapter 2 Flashcards
Atomic theory
The concept of an atom
Born in Ancient Greece (~500bc)
Chemical basis of life
Atoms, molecules, and properties of H2O
Atomic structure
The nature of an atom
Proton, neutron, electron, ion, isotopes
Atomos
All matter is made up of tiny invisible particles named
Matter
Has mass and occupies space
Matter is
Composed of chemical elements.
Gas, solid, liquid, plasma
Element
Has atomic characteristics and cannot be broken down into other substances
Atom
Smallest unit of matter with retains the chemical and physical properties of an element
Proton
Electron
Neutron
Positive
Negative
No charge
Atomic structure
Nucleus composed of protons and neutrons and surrounded by orbiting electrons. Protons and neutrons have roughly the same mass (1 dalton)
Atomic number
Same as number of protons
Atomic mass and weight
Mass of protons and neutrons combined
All atoms of an element have?
The same atomic number and mass
In a neutral atom?
Number of protons = number of electrons
Isotopes
Atoms must have a certain # of protons to retain the characteristics of a given element, but # of neutrons sometimes vary.
Unstable and decay at constant rate
Electrons
Orbit around nucleus (drawn by protons + charge)