8F Periodic table revision

Why were there blank spaces left in Mendeleev's periodic table?                                              

• He didn't know what to put there.
•  Undiscovered elements not yet known.
• Multiple elements could have fit
• He forgot to add the elements in.

Which property did Mendeleev use to order his periodic table?

• Shielding effect
• Eletronegitivity
• Atomic Weight
• Metallic Character

The horizontal row on the periodic table is called a

• group
• family
• period
• atomic number

What is the chemical symbol for Lithium?

• H
• He
• Li
• N

Most of the elements on the periodic table are classified as _____.

• Metals
• Nonmetals
• Metalloids
• Periods

Each column in the periodic table is called a 

• period
• group
• cluster
• unit

Which group of the periodic table is composed of inert (not reactive)  gases?

• alkali metals
• alkaline earth metals
• halogens
• noble gases

Elements which are shiny, conduct electricity and heat are called

• metal
• nonmetal
• metalloid
• nonexistent

Which is an alkali metal?

• Magnesium
• Iron
• Sodium
• Europium

Which is a halogen?

• Helium
• Chlorine
• Oxygen
• Neptune