Chapter 3b Metallic Bonding

Delocalised electrons are best described as

• red balls with a negative charge.

• valence electrons that are free to move.

• electrons that have nowhere local to go.

• red balls with a negative charge that can move easily.

Sodium atoms form Na⁺ ions because

• they have one valence electron and lose it.

• they have one valence electron and gain another one.

The ionic charges expected for the period 4 elements K, Ca and Sc are

• K⁺, Ca²⁺ & Sc²⁺

• K⁺, Ca²⁺ & Sc³⁺

• K⁺, Ca⁺ & Sc⁺

• K⁴⁺, Ca⁴⁺ & Sc⁴⁺

The regular arrangement of delocalised electrons and metal cations is described as a

• lattice

• grid

• array

• spread

Metals are generally hard & have high melting points. The best explanation for this is that

• delocalised electrons move throughout the metallic lattice.

• metallic bonds are multi-directional.

• the electrostatic force of attraction between cations and delocalised electrons is strong.

• metallic atoms pack closely together.

Metals are malleable and ductile. The best explanation for this is that

• delocalised electrons move throughout the metallic lattice.

• metallic bonds are multi-directional.

• the electrostatic force of attraction between cations and delocalised electrons is strong.

• metallic atoms pack closely together.

All metallic properties are due to the presence of delocalised electrons.

• True

• False