Composed of individual particles that have the same properties.
element
The basic indivisible particle of which matter is made.
atom
A measure of the amount of matter in an atom.
mass
A combination of 2 or more atoms.
molecule
An atom or molecule with an electrical charge.
ion
Subatomic particle found in the nucleus, has mass, and a positive charge.
proton
Subatomic particle found in the nucleus, has mass, and is neutral - no electrical charge.
neutron
Subatomic particles found in spheres hovering around the nucleus; very little mass (basically zero), but a
negative electrical charge
electrons
Region in the middle of an atom, where the mass is centered; composed of protons and neutrons.
nucleus
Basic rule on electrons: do they like to be separate, in pairs, or in other groups?
pairs
Maximum number of electrons in the first energy level, closest to the nucleus.
2
Maximum number of electrons in the second energy level.
8
For small atoms, maximum number of electrons in the third energy level.
8
True or false: the basic rule on electrons is fill the first energy level before putting electrons in the second, and fill the second before putting electrons in the third.
true
The chemical symbol for the element hydrogen.
H
The chemical symbol for the element carbon.
C
The chemical symbol for the element nitrogen.
N
The chemical symbol for the element oxygen.
O
The chemical symbol for the element sodium.
Na
The chemical symbol for the element magnesium.
Mg
The chemical symbol for the element phosphorus
P
The chemical symbol for the element potassium.
K
The chemical symbol for the element calcium.
Ca
What does the row number in the Periodic Table mean?
number of energy levels (shells) occupied by electrons
What does the column number in the Periodic Table mean?
number of electrons in the valence shell
What's so special about the elements in column VIII?
