The number of valence electrons in an atom can often be quickly determined by referencing
a. the atomic number of the element.
b. the period number on the periodic table.
c. the atomic mass of the element.
d. the group number on the periodic table

Which best explains why the number of states in the world increased significantly between 1985 and 1995? the map of southeast asia was redrawn, and new countries were formed. new states were formed when the soviet union collapsed. many african states received independence from their colonizers. communist countries seeking to spread their influence created new satellite states. civil wars in central america fueled the creation of new states.