Bonding, Structure and Properties of Matter (Chemistry) Flashcards
6 cards from real GCSE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Bonding, Structure and Properties of Matter (Chemistry) flashcards as text
Which statement best describes metallic bonding?
Answer: A regular arrangement of positive metal ions surrounded by a sea of delocalised electrons
Metals consist of a giant structure of positive ions in a sea of delocalised electrons; the electrostatic attraction between them is the metallic bond.
Why is an alloy such as brass harder than pure copper?
Answer: The different-sized atoms distort the layers, making it harder for them to slide over each other
In a pure metal the layers of identical atoms slide easily; in an alloy, atoms of different sizes disrupt the regular layers so they cannot slide as easily.
A nanoparticle has a diameter of 50 nm. Which of these correctly expresses 50 nm in metres?
Answer: 5 × 10⁻⁸ m
1 nm = 1 × 10⁻⁹ m, so 50 nm = 50 × 10⁻⁹ m = 5 × 10⁻⁸ m.
Which change of state is called sublimation?
Answer: Solid directly to gas
Sublimation is when a solid turns directly into a gas without passing through the liquid state, as with solid carbon dioxide (dry ice).
What is a limitation of the simple particle model used to describe solids, liquids and gases?
Answer: It assumes particles are solid, inelastic spheres with no forces between them
The simple model treats particles as small solid spheres and does not show the forces between them or that particles are not actually solid.
Which type of structure does silicon dioxide (silica, SiO₂) have?
Answer: Giant covalent
Silicon dioxide is a giant covalent structure in which each silicon atom bonds to four oxygen atoms and each oxygen to two silicon atoms.