22.1.1 General Properties of Nonmetals

Question 1

General Properties of Nonmetals

Answer 1

• Nonmetals have very different properties from metals.

* Elements of the second period tend to form pi bonds, while other elements do not

Question 2

note

Answer 2

• The nonmetals are main-group elements in the upper-right corner of the periodic table.
• Nonmetals have very different properties from metals. Most nonmetals are gases (H, N, O, F, Cl, and the noble gases) but they also exist as liquids (Br) and solids (C, P, S, Se, I).
• Nonmetals can have multiple oxidation states, both negative and positive. Metals in the main group tend to have only a single positive oxidation state. Transition metals may have several oxidation states, but all are usually positive. Nonmetals tend to be electronegative, thus they tend to form ionic bonds with metals and covalent bonds with other nonmetals.
• Elements of the second period tend to form pi bonds, while other elements do not.
• For example, nitrogen in its elemental form is a triple-bonded diatomic gas. Phosphorus, below nitrogen and in the same family, is a solid consisting of four atoms with single bonds between them.
• Likewise, oxygen in its elemental form is a diatomic gas with double bonds. Sulfur, below oxygen on the periodic table, is a solid made up of molecules with eight atoms of sulfur with single bonds between them.
• In another example, carbon dioxide (CO 2 ) is a three-atom molecule with double bonds holding the oxygen atoms to the carbon atom. Silicon dioxide (SiO 2 ) is an
  extended network solid with single bonds between atoms.

Question 3

Which of the following has the ability to possess either positive or negative oxidation states or charge?

Answer 3

Nonmetals

Question 4

For the following nonmetal compounds or ions, oxidation states (or oxidation numbers) have been assigned to all atoms. Which has the oxidation states INCORRECTLY assigned?

Answer 4

NO3− N is +6 O is −2

Question 5

Which of these compounds contains only sigma (σ) bonds?

Answer 5

S8

Question 6

Complete the following analogy:

Ammonia : phosphine :: methane : _________________

Answer 6

Silane

Question 7

Which of the following groups is INCORRECT?

Answer 7

Alkali metals: H, Li, Na, K, Rb, Cs, Fr

Question 8

Which of the following elements shows the least propensity for π-bonding in compounds?

Answer 8

Boron

Question 9

Which of the following homonuclear molecular species contains π bonds?

Answer 9

N2

Question 10

Which of the following elements is not a liquid at 29.5 ° C?

Answer 10

Ga

Question 11

When the elements C, N, and O are compared with those directly below them on the periodic table (Si, P, and S), the following is observed:

CO2 is a trinuclear molecular species that is a gas at room temperature, while SiO2 is an extended network solid.
N2 exists as a gas, but the elemental form of phosphorus, P4, is a tetrahedral solid.
Oxygen gas is a diatomic molecule, but sulfur exists as solid S8.

What phenomenon do these observations demonstrate?

Answer 11

Overlap in the 2p orbitals tends to increase π-bonding.

Question 12

In which of the following compounds would you expect to find only polar covalent bonds?

Answer 12

PBr3