B
These are the horizontal rows on the periodic table.
What are periods?
These are the vertical columns on the periodic table whose elements have similar chemical properties.
What are groups (or families)?
This number tells how many protons are in the nucleus of an atom.
What is the atomic number?
This is the weighted average mass of all naturally occurring isotopes of an element.
What is atomic mass?
Elements in this group have one valence electron and are highly reactive metals.
What are the alkali metals?
These Group 2 elements have two valence electrons and are reactive, but less reactive than alkali metals.
What are the alkaline earth metals?
These elements are found in the center of the periodic table and are good conductors of heat and electricity.
What are the transition metals?
These elements are poor conductors of heat and electricity and are found on the right side of the periodic table.
What are nonmetals?
These elements have properties of both metals and nonmetals.
What are metalloids?
These Group 17 elements are highly reactive nonmetals with seven valence electrons.
What are the halogens?
These Group 18 elements are very unreactive because they have full valence shells.
What are the noble gases?
This "stair-step" line on the periodic table separates metals from nonmetals.
What is the metalloid (zigzag) line?
As you move from left to right across a period, atomic radius generally does this.
What is decreases?
As you move down a group, atomic radius generally does this.
What is increases?
This trend measures an atom's ability to attract electrons in a chemical bond.
What is electronegativity?
Electronegativity generally increases in this direction across the periodic table.
What is from left to right?
Ionization energy is the energy required to do this to an atom.
What is remove an electron?
Ionization energy generally increases in this direction across a period.
What is from left to right?
This trend describes the size of an atom.
What is atomic radius?
The elements in the same group all have this in common regarding their outer electrons.
What is the same number of valence electrons?
These elements are shiny, malleable, ductile, and good conductors of heat and electricity.
What are metals?
These elements tend to gain electrons when they form ions.
What are nonmetals?
These elements tend to lose electrons and form positive ions.
What are metals?
This is the most reactive metal on the periodic table because it is located at the bottom of Group 1.
What is francium?
This region at the bottom of the periodic table contains the lanthanides and actinides.
What is the inner transition metals (or f-block)?