Defining the Atom Chapter 4 (Determining an Atom (Atomic Number…
Defining the Atom Chapter 4
Definition: The smallest particle of an element that retains its identity in a chemical reaction.
Greek philosopher who suggested the existence of atoms ant believed they were both invisible and indestructible.
Dalton's Atomic Theory
All elements are composed of tiny invisible particles called atoms.
All matter has mass
determines the atomic number
Large particle(1840x the mass of electron)
Determining an Atom
Average mass of the atoms in a naturally occurring sample of the element
Atoms with same number of protons but different number of neutrons.
Example Neon-21;10 protons, 11 neutrons, 10 electrons
The total number of protons and neutrons
Determined by number of protons
Ina neutral atom the atomic number=the#of protons and the #of electrons