4. Atoms and Elements

Which of the following elements is classified as a metalloid?

Periodic Table: Classifications — Who is credited with developing the first widely recognized periodic table by arranging elements according to increasing atomic mass and predicting properties of undiscovered elements?

In the periodic table, the horizontal rows are called what?

Where are metal atoms primarily located on the periodic table?

Which element is located in Group 2 and Period 3 of the periodic table?

In the periodic table, what is the name for a vertical column?

How did Dmitri Mendeleev primarily arrange the periodic table in his original 1869 version?

Who is most commonly credited with creating the first widely recognized periodic table (1869) by arranging elements according to recurring chemical properties?

Which element is the most abundant in the universe by mass?

In the periodic table, what is a horizontal row called?

Periodic Table: Classifications — Why isn’t water ($H_{2}O$) on the periodic table?

Which Group 15 element is classified as a metal?

On the periodic table, are there more metals or nonmetals?

In the periodic table, what are the horizontal rows called?

Most of the elements on the periodic table are classified as which type of element?