5-2 Notes – Forming Solids

Chapter 5, Lesson 2

Metals• Metals make up about 2/3 of the elements

and have many useful properties.

Metals• usually shiny

Metals• good conductors of electricity and heat

because their electrons are free to move

Metals• solid at room temperature

Metals• high melting point and high boiling point

Metals• malleable - ability to be hammered or rolled

into sheets

Metals• ductile - ability to be pulled into a wire

• Metals can bond to atoms of the same element, or to other metals

• A metallic bond is a bond formed when many metal atoms share their pooled electrons.

Metals

• Atoms (or molecules) of metal in solids pack together as closely as possible in a regular, three-dimensional pattern

• Metal atoms combine in regular patterns in which some electrons are free to move from atom to atom.

• In a metal, individual atoms lose electrons to become positive ions.

Metals

• Crystals are regular, repeating arrangements of atoms, ions, or molecules.

• Crystals can be held together by metallic, ionic, or covalent bonds.

Crystals

• A unit cell is the smallest repeating pattern that shows how the atoms, ion, or molecules are arranged in a crystal.

Crystals

• One common crystal is table salt, also known as sodium chloride.– Sodium chloride, NaCl, is an

ionic crystal.– Ionic crystals are brittle, unlike

solid metals.

Crystals

• “poly” means many.• Polymers are covalent compounds

made up of many small, repeating units linked together in a chain.

• A monomer is a small molecule that forms a link in a polymer chain.

• Many hundreds of monomers link together to form a solid polymer.

Polymers

Polymers

• Some polymers are synthetic. This means they are human-made in a factory.

• Polyethylene is a synthetic polymer used for grocery bags and food wrap.

Polymers

• Organic polymers are polymers that contain the element carbon and are involved with life.

• Carbon has 4 valence electrons. • It NEEDS 4 more to make 8. • Carbon SHARES its 4 valence electrons

in 4 covalent bonds.

Polymers

• All living cells must contain three important kinds of natural organic polymers:

1. proteins

2. carbohydrates

3. nucleic acids

Polymers

• The monomer of a protein is an amino acid, which includes carbon, nitrogen, and oxygen atoms.

Polymers

• The monomer of a carbohydrate (also called a polysaccharide) is a sugar molecule called a monosaccharide.

Polymers

What holds carbohydrates together?

A ionic bonds

B metallic bonds

C covalent bonds

D electron clouds

5.2 Forming Solids

Which of the following is the most malleable?

A crystal

B polymer

C metal

D monomer

5.2 Forming Solids

A(n) ____ is the smallest repeating pattern in a crystal.

A monomer

B polymer

C metallic bond

D unit cell

5.2 Forming Solids

Which is an example of a natural polymer?

A sodium chloride

B polyethylene

C polysaccharide

D quartz

A polymer is made up of many repeating monomers held together by ____.

A metallic bonds

B polymer chains

C ionic bonds

D covalent bonds

Metals are good conductors because ____.

A their electrons move freely

B their protons move freely

C they have ionic bonds

D none of the above

SCI 3.c

Which property of copper allows it to be pulled into wires?

A ductility

B malleability

C conductivity

D luster

SCI 7.c