Bell Work

• Name three common traits for each of the following: Alkali Metals, Alkaline Earth Metals, Lanthanides, and Actinides.

Physical Science – Lecture 60

Non-Metals and Metalloids

Metalloids

• Elements that have some properties of metals and some properties of nonmetals are called metalloids.

What are the Properties of the Metalloids?

• The boiling points, melting points, and densities of the metalloids vary.

• The metalloids make good semiconductors.

Where are the Metalloids?

• The metalloids are located along the diagonal line between the metals and nonmetals in the periodic table.

Nonmetals

• Elements that don't have the properties of metals are called nonmetals.

Where are the Non-metals?

• The nonmetals are located on the upper right side of the periodic table, separated from metals by a line that cuts diagonally through the periodic table.

Who’s in the Family?

• The nonmetal element group is usually considered to consist of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, and selenium.

• It also includes halogens and noble gases.

Common Traits of Nonmetals

• The nonmetals are poor conductors of heat and electricity.

• Solid nonmetals are brittle and lack metallic luster.

• Most nonmetals gain electrons easily.

Common Traits of Non-Metals

• Nonmetals have high ionization energies and electronegativities.

THE NOBLE or INERT GASES

• These gases are located in the far right column of the periodic table.

• This is group 8A, 18 or 0 depending on the textbook.

WHO'S IN THE FAMILY?

• Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

Noble Gases

• All of the inert gases have full outer shells with 8 electrons (except Helium who only has 2).

• This makes them non-reactive.

Common Traits of Noble Gases

• The noble gases have low boiling points and are all gases at room temperature.

Their Usefulness

• Neon is used in advertising signs. • Argon is used in light bulbs. • Helium is used to cool things and in balloons. • Xenon is used in headlights for new cars.

Summary of Common Properties

• Fairly nonreactive • Complete valence shell • High ionization energies • Very low electronegativities • Low boiling points (all gases at room

temperature)

HALOGENS

• Halogens (halogen family) are in Group 17 or 7A.

Who is in this family?

• The elements included are Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At).

Shared Traits

• They all have seven electrons in their outer shell.

• They need one electron to have a full shell.•

Common Traits

• Halogens range from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2) at room temperature.

• The halogens have very high electronegativities.

• These nonmetals form ions with a -1 charge.

Reactivity

• Fluorine is actually the most reactive element of all. It is a halogen.

• As you move down the group, reactivity decreases for the halogens.

HALIDES

• When a halogen combines with another element, the resulting compound is called a halide.

Their Usefulness

• You find these elements in bleaches, disinfectants, and salts.

Summary of Common Properties

• Very high electronegativities • Seven valence electrons (one short of a stable

octet) • Highly reactive, especially with alkali metals

and alkaline earths

Groups 13-15: Not all one Type

• Groups 13-15 include some metals, some metalloids, and some nonmetals.

• The transition from metal to nonmetal is gradual across the periodic table.

Common Trends in Mixed Groups

• Remember that even in mixed groups of elements, the trends in the periodic table still hold true.

• Atom size, ease of removing electrons, and ability to form bonds can be predicted as you move across and down the table.