Structures and Properties of Materials

Front

What is the difference between an element, compound, and mixture in terms of composition?

Back

Element: Made up of only one type of atom. Compound: Made up of more than one type of atom chemically combined. Mixture: Made up of more than one type of substance physically combined.

Front

What are the melting and boiling point characteristics of elements and compounds?

Back

Elements and compounds have fixed melting and boiling points (pure substances). Mixtures melt/boil over a range of temperatures.

Front

How can elements, compounds, and mixtures be separated?

Back

Elements cannot be further decomposed. Compounds are separated by chemical means (e.g., electrolysis). Mixtures are separated by physical means (e.g., filtration, chromatography).

Front

What is the main difference in electrical conductivity between ionic and covalent compounds?

Back

Ionic compounds can conduct electricity in molten and aqueous states due to mobile ions, while covalent compounds cannot conduct electricity at all.

Front

Why does sodium oxide have a high melting and boiling point compared to carbon dioxide?

Back

Sodium oxide is an ionic compound with a giant ionic lattice structure, requiring a lot of energy to overcome strong electrostatic forces. Carbon dioxide is a covalent compound with a simple molecular structure, needing little energy to overcome weak intermolecular forces.

Front

What are the general properties of metals?

Back

Good conductors of electricity and heat, high melting and boiling points (except group 1 metals), malleable and ductile.

Front

What is an alloy? Give an example.

Back

An alloy is a mixture of metal with other elements. Example: Steel (iron and carbon), Brass (copper and zinc).

Front

What is one main advantage of alloys over pure metals?

Back

Alloys are stronger and harder than pure metals.

Front

What type of bonding occurs between metals and non-metals?

Back

Ionic bonding.

Front

What type of bonding occurs between non-metals?

Back

Covalent bonding.