5.1 and 5.2 Flashcards
1
Q
periodic
A
describes something that occurs or repeats at regular intervals.
2
Q
periodic law
A
the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements.
3
Q
period
A
horizontal row of elements on the periodic table.
4
Q
group
A
the vertical column of elements in the periodic table.
5
Q
alkali metal
A
elements in group one of the periodic table.
6
Q
alkaline-earth metal
A
are less reactive than alkali metals are.
7
Q
halogen
A
are very reactive nonmetals because their atoms need to gain only one electron to have a complete outer level.
8
Q
noble gas
A
are unreactive nonmetals and are in group 18 of the periodic table.
