Which of the following describes the arrangement of atoms in a metal?
A
Random and disordered B
Tightly packed and crystalline C
Spherical and hollow D
Layered and porous
Analysis & Theory
Metals have a tightly packed crystalline structure that is highly ordered.
Which is NOT a common crystal structure found in metals?
A
Body-Centered Cubic (BCC) B
Face-Centered Cubic (FCC) C
Hexagonal Close-Packed (HCP) D
Simple Cubic (SC)
Analysis & Theory
Simple Cubic is rare in metals due to its low packing efficiency.
Which crystal structure has the highest packing efficiency?
A
BCC B
FCC C
HCP D
SC
Analysis & Theory
FCC and HCP both have high packing efficiency, but FCC is more ductile.
Alloys are made by combining:
A
Metals with gases B
Two or more metals C
Metals with acids D
Metals with water
Analysis & Theory
Alloys are mixtures of two or more metals or a metal and a non-metal.
Brass is an alloy of:
A
Copper and Zinc B
Copper and Tin C
Iron and Carbon D
Aluminum and Iron
Analysis & Theory
Brass is an alloy of copper and zinc.
Steel is an alloy of:
A
Iron and Zinc B
Iron and Copper C
Iron and Carbon D
Iron and Lead
Analysis & Theory
Steel is primarily composed of iron with a small percentage of carbon.
What type of alloy is formed when the atoms of the added element replace host metal atoms?
A
Interstitial alloy B
Substitutional alloy C
Random alloy D
Amorphous alloy
Analysis & Theory
In substitutional alloys, the atoms of the second element replace host atoms in the lattice.
In interstitial alloys, the added atoms occupy:
A
The surface of the metal B
Lattice positions C
Void spaces between metal atoms D
The center of the metal grain
Analysis & Theory
In interstitial alloys, smaller atoms fit into the spaces between the larger host atoms.
Which property of metals is enhanced by alloying?
A
Brittleness B
Reactivity C
Hardness and strength D
Radioactivity
Analysis & Theory
Alloying often increases the hardness, strength, and corrosion resistance of metals.
Which of the following is an example of an **intermetallic compound**?
A
Brass B
Steel C
Stainless Steel D
Al3Ni
Analysis & Theory
Al₃Ni is a fixed-ratio intermetallic compound with a defined crystal structure.