History of the Periodic Table
Who is credited with creating the first periodic table?
Dmitri Mendeleev
In an atom, the number of protons equals the number of this
What is electrons?
What do elements in the same column share?
Similar properties
What property does NOT describe most metals?
liquid at room temperature
Which elements have properties of both metals and nonmetals?
Metalloids
Mendeleev created the first periodic table by arranging elements in order of this
What information in the periodic table indicates the number of protons in an atom?
atomic number
What are the vertical columns on the periodic table called?
Groups
This term means a metal can be drawn into a wire
What is ductile?
What family contains the most reactive metals?
Alkali Metals
How did chemists change Mendeleev’s periodic table in the early 1900s?
They used atomic number instead of atomic mass to organize the elements.
These particles in atoms have a negative electric charge
What are electrons?
What are the horizontal rows on the periodic table called?
Periods
What property allows a metal to be hammered into thin sheets?
Malleable
The elements that do not ordinarily form compounds are these.
What are noble gases?
What did Mendeleev do when no known element fit a pattern?
left gaps for undiscovered elements
This is the dense center of an atom
What is the nucleus?
In the periodic table, the most reactive metals are found ____.
Group 1
This describes metals that easily transfer heat and electricity
What is a good conductor?
Fluorine, chlorine, bromine, and iodine are part of a family called ____.
What are halogens?
He proved that atomic number determines an element’s identity?
Who is Henry Moseley?
The second outer energy level of an atom can hold a maximum of ____ electrons.
What are 8?
This category of elements makes up most of the periodic table?
What are metals
What are examples of transition metals?
The two most common alkaline earth metals are ____.
Calcium and Magnesium