6.4 The Structure of Metals

What are the forces that give a ___________ its structure as a solid?

Metallic Bonds

The _____________ in a metal form a lattice that is held in place by strong metallic bonds between the cations and the surrounding ____________________________.

6.4 The Structure of Metals

Metal atoms achieve stable electron configurations by __________________ electrons. What happens if there are no nonmetal atoms available to accept the electrons?

In a metal, valence electrons are free to _________ among the atoms. In effect, the metal atoms become cations surrounded by a pool of shared electrons.

Metallic Bonds

6.4 The Structure of Metals

A _______________ bond is the attraction between a metal cation and the shared electrons that surround it.

Although the _______________ are moving among the atoms, the total number of electrons does not change. So, overall, the metal is neutral.

Metallic Bonds

6.4 The Structure of Metals

How do _______________ bonds produce some of the typical properties of metals?

Explaining Properties of Metals

The ________________ of electrons within a metal lattice explains some of the properties of metals.

6.4 The Structure of Metals

The mobility of electrons within metals affects the properties of metals. The ability to _____________ an electric _____________ and _____________________ are two important properties of metals.

A metal has a built-in supply of charged particles that can flow. An electric current can be carried through a metal by the free flow of the shared electrons.

Explaining Properties of Metals

6.4 The Structure of Metals

In a metal, cations are surrounded by shared valence electrons. If a metal is struck, the ions _____________ to new positions, but the ions are still surrounded by electrons.

Explaining Properties of Metals

Hammer strikes metal. Metal changes shape but does not break.

6.4 The Structure of Metals

How are the properties of __________ controlled?

Alloys

Scientists can design alloys with specific properties by varying the types and amounts of elements in an alloy.

An _____________ is a mixture of two or more elements, at least one of which is a metal. Alloys have the characteristic properties of __________________.

6.4 The Structure of Metals

Steel AlloysSteel is an alloy of iron that contains small quantities of carbon, ranging from less than 0.2 percent to about 3 percent by mass. The smaller carbon atoms fit in the spaces between the larger iron atoms in the lattice. The carbon atoms form bonds with neighboring iron atoms. These bonds make the lattice harder and stronger than a lattice that contains only iron.

Alloys

6.4 The Structure of Metals

The properties of steel depend on which elements in addition to iron and carbon are used to make the steel and how much of those elements are included.

• Stainless steels contain more than 10 percent chromium by mass, but almost no carbon.

• Stainless steels are durable and do not rust.• Stainless steels are more brittle than steels

with more carbon.

Alloys

6.4 The Structure of Metals

Assessment Questions

1. What force holds the atoms of a metal together? a. the attraction of a positively charged atom to a

negatively charged atom

b. the sharing of electrons between two atoms

c. the gravitational force between dense metal atoms

d. the attraction between metal cations and a pool of shared electrons

6.4 The Structure of Metals

Assessment Questions

2. Why are solid metals good conductors of electric current?a. Metals are good conductors because they can be drawn

into wires.b. Metals are good conductors because they are solids at

room temperature.c. The nuclei of metal atoms can move easily because

they repel one another.d. Shared electrons are able to flow freely through the

metal.

6.4 The Structure of Metals

Assessment Questions

1. The properties of bronze depend on the ratio of iron, carbon, and small amounts of other elements in the alloy.

TrueFalse