Unit 2.2

If an element is located in the middle of the periodic table, into what category would it most likely fit?

• nonmetal

• metalloid

• metal

• noble gases

The atomic mass of gold (Au) is 198, and the atomic number is 79. How many neutrons does a neutral atom of gold contain?

• 79

• 119

• 198

• 99

Which family of elements contains a full outer shell of electrons?

• noble gases

• lanthanides

• transition metals

• halogens

Helium is placed in group 18 on the periodic table because...

• it is highly reactive.

• it has a valence of eight.

• it is a metal.

• it has a full outer shell of electrons.

The term element refers to atoms that have the same number of...

• neutrons.

• protons.

• electrons.

• ions.

Which is a gas at room temperature?

• aluminum

• nitrogen

• potassium

• bromine

Iron (Fe) can have an oxidation number of 2+ or 3+. This means that iron can lose either 2 or 3 electrons when combining with other atoms. Into which of the following groups is iron placed?

• transition metals

• lanthanide series

• alkali metals

• halogens

A neutral atom always contains the same number of...

• protons and electrons.

• electrons and neutrons.

• protons and neutrons.

• protons, electrons, and neutrons.

Members of the alkaline earth elements have several things in common. They are...

• nonmetals and are nonreactive.

• metals that are not very reactive.

• metals with two valence electrons.

• metalloids with two valence electrons.

The periodic table contains many trends that are predictable as you go across a period or down a group. Atomic radius as you go across a period from left to right _______ and as you go down the group ________.

• increases, increases

• decreases, decreases

• increases, decreases

• decreases, increases