Chapter 7- Lesson 3 NotesNon Metals and MetalloidsLesson 3 has been discussed and reviewed. Students should have 3

questions on each of the note pages. For periods 1,3,5,7- notes go on NB 44 and 46. Vocabulary from pg 248 goes on NB 43 with a Bellringer. The NonMetals packet will go on NB 45. For periods 2 and 4- notes go

on NB 42 and 44. Vocabulary from pg 248 goes on NB 41 with a Bellringer. The NonMetals packet will go on NB 43.

Lesson 3-1More than 96 percent of the mass of the human body comes from four nonmetals–oxygen, carbon, hydrogen, and nitrogen.

The Elements of Life

Lesson 3-1• Nonmetals are elements that have no metallic

properties.

• The four elements that make up most of the human body, along with phosphorus and sulfur, are the six elements in proteins, fats, nucleic acids, and other large molecules in your body and in all other living things.

The Elements of Life (cont.)

Lesson 3-2

• Nonmetals have properties that are different from those of metals.

• Many nonmetals are gases at room temperature and those that are solid at room temperature have a dull surface, which means they have no luster.

• Because nonmetals are poor conductors of electricity and thermal energy, they are good insulators.

How are nonmetals different from metals?

Lesson 3-2Phosphorus and carbon are dull, brittle solids that do not conduct thermal energy or electricity.

Lesson 3-2

An element in group 17 of the periodic table is galled a halogen.

How are nonmetals different from metals? (cont.)

Lesson 3-2

The term halogen refers to an element that can react with a metal and form a salt.

How are nonmetals different from metals? (cont.)

Lesson 3-2

• Halogens react readily with other elements and form compounds.

• Halogens can only occur naturally in compounds.

• In general, halogens are less reactive as you move down the group.

How are nonmetals different from metals? (cont.)

Lesson 3-2

The elements in group 18 are known as the noble gases.

How are nonmetals different from metals? (cont.)

Lesson 3-2

• Unlike the halogens, the only way elements in this group react with other elements is under special conditions in a laboratory.

• Of all the elements, hydrogen has the smallest atomic mass and is the most common element in the universe.

How are nonmetals different from metals? (cont.)

Lesson 3-2

• Hydrogen is most often classified as a nonmetal because it has many properties like those of nonmetals.

• However, hydrogen also has some properties similar to those of the group 1 alkali metals.

• Under conditions on Earth, hydrogen usually behaves as a nonmetal.

How are nonmetals different from metals? (cont.)

Lesson 3-3Between the metals and the nonmetals on the periodic table are elements known as metalloids.

Lesson 3-3• A metalloid is an element that has physical and

chemical properties of both metals and nonmetals.

• The elements boron, silicon, germanium, arsenic, antimony, tellurium, polonium, and astatine are metalloids.

• Silicon is the most abundant metalloid in the universe.

Metalloids (cont.)

Lesson 3-3• A property of metalloids is the ability to act as a

semiconductor.

• A semiconductor conducts electricity at high temperatures, but not at low temperatures.

Metalloids (cont.)

Lesson 3-3Silicon is used in making semiconductor devices for computers and other electronic products.

Metalloids (cont.)

Lesson 3-4

• An element’s position on the periodic table tells you a lot about the element.

• Understanding the properties of elements can help you decide which element to use in a given situation.

Metals, Nonmetals, and Metalloids