1
Electrons in the outer-most energy level that participate in bonding (Same group=same # of valence electrons)
Valence Electrons
refers to how likely or vigorously an atom is to react with other substances
Reactivity
The nucleus is made up of _______ and ________?
Protons and Neutrons
A charged particle (caution-positive, anion-negative)
Ion
Protons + Neutrons, a decimal on the periodic table because it's an average of different isotopes
Atomic Mass
Atoms have the same number of _______ and ________?
Protons and Electrons
rows on the periodic table, elements have the same number of energy levels
Periods
Protons have a charge of _____?
+1
(families) columns on the periodic table, elements have the same number of valence electrons
Groups
Neutrons have a charge of ____?
0
two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
Isotopes
Electrons have a charge of _____?
-1