The Periodic Table

Atoms of elements that are in the same group have the same number of

• protons.

• neutrons.

• valence electrons.

• protons and neutrons.

Which of the following elements is an alkali metal?

• calcium

• magnesium

• mercury

• sodium

Mendeleev left gaps in his periodic table because

• the table was too small.

• protons belonged there.

• the table was too full.

• no known elements fit there.

The three main groups of elements are metals, nonmetals, and

• inert gases.

• alkali metals.

• radioactive isotopes.

• semiconductors/metalloids.

The order of elements in the modern periodic table is based on an element's

• atomic number.

• name.

• chemical symbol.

• atomic mass.

Which statement about the alkali metals is correct?

• They are located in the left-most column of the periodic table.

• They are extremely nonreactive.

• They are usually gases.

• They form negative ions with a 1- charge.

Metals tend to be

• gases.

• dull.

• brittle.

• good conductors.

Which group is very stable due to the fact that they have a full outermost energy level?

• alkali metals

• halogens

• alkaline-earth metals

• noble gases

Based on its location on the periodic table, which of these elements most likely has physical and chemical properties most similar to boron (B)?

• magnesium (Mg)

• aluminum (Al)

• neon (Ne)

• chlorine (Cl)

Alkali metals are extremely reactive because they

• have every small atomic masses.

• are not solid at room temperature.

• have one valence electron that is easily removed to form a positive ion.

• have two valence electrons that form compounds with calcium and magnesium.