Chemistry Review Flashcards
Democritus
argued that everything in the world is made of particles so small that they cannot be cut in half (he called them atoms)
Dalton
discovered that atoms are the smallest part of an element that keeps its chemical properties.
Atoms
the building blocks of matter
Element
a group of all the same type of atom
Nucleus
the center of an atom (contains protons and neutrons)
Proton
particle of an atom
positive charge
Larger and heavier than electrons
located in the nucleus
Electrons
particle of an atom
negative charge
tiny and light
move around the outside of the nucleus (in shells)
Neutrons
particle of an atom
no electrical charge
large and heavy
located in nucleus
Strong Force
this holds the nucleus together, keeping the protons and neutrons together
Atomic Number
number of protons found in an element, and in a stable element (all the ones we’re working with), number of electrons.
Atomic Mass
The mass of an atom (nucleus)
Shells
energy levels where the electrons are found
Smallest to largest-Molecule-Element-Compound-Atom
Atom-Element-Molecule-Compound
(pure elements are shown on the periodic table. Molecules exist in nature and can be shown as H2O, CO2, and H2.)
6
C
Carbon
12.011
Atomic Number=6
Atomic Mass=12.011 (decimal because it is a weighted average of all the atoms)
Symbol=C
Number of Protons=6
Number of Electrons=6
Number of neutrons=6 (atomic mass-atomic number)
Compounds
substance made up of molecules that contains more than one kind of atom
