Chapter 3 Structure and Bonding Flashcards
Describe the movement and arrangement of particles in a solid.
The particles in a solid are packed closely together and vibrate around fixed positions.
Describe the movement and arrangement of particles in a liquid.
The particles in a liquid are close together but are free to move so can move over each other.
Describe the movement and arrangement of particles in a gas.
The particles in a gas have lots of space between them and they move quickly and randomly.
Why do some substances have higher melting and boiling points than other substances?
The stronger the forces between the particles are, the more energy is required for melting or boiling. This results in higher melting and boiling points.
What happens at the melting point of a substance?
Melting and freezing take place at the melting point.
What happens at the boiling point of a substance?
Boiling and condensing take place at the boiling point.
What are the limitations of the simple particle model for states of matter?
The simple particle model has limitations. There are no forces in the model and all particles are represented as solid spheres.
Give the 4 state symbols and state what they stand for.
We use state symbols to represent the different states in chemical equations. The state symbols are:
What is a compound?
A compound is a substance made up of 2 or more elements which have chemically combined.
Name the 3 types of strong chemical bonds?
There are 3 types of strong chemical bonds: ionic, covalent and metallic.
Between which types of elements do ionic bonds form?
Ionic bonds are formed between metals and non-metals.
What types of ions will metal elements form?
Metal atoms will lose electrons to become positive ions and to have a stable full outer shell of electrons.
What types of ions will non-metal elements form?
Non-metal atoms will gain electrons to become negative ions and have a full outer shell of electrons.
Why would an atom gain or lose electrons?
Atoms will gain or lose electrons to achieve a full outer shell so they have the same electron configuration as their nearest noble gas.
How do ionic bonds form?
To form an ionic compound electron transfer takes place. Electrons move from a metal to a non-metal.
Name the forces that hold ions together in an ionic bond.
Ions are held together in ionic compounds by electrostatic forces of attraction between the positively charged metal ion and the negatively charged non-metal ion.
What type of diagram do we use to represent electron transfer?
Electron transfer during the formation of an ionic compound can be represented by a dot and cross diagram.
What is the overall charge on an ionic compound?
Ions combine so that the overall charge on the compound is zero. For example magnesium forms an ion with a charge of 2+ so will combine with 2 chloride ions that each have a charge of 1-. The formula would be Mg2+(Cl-)2
What makes a crystal lattice strong?
Ionic compounds are giant structures of ions arranged as a crystal lattice. Each ion is surrounded by oppositely charged ions in all directions making the structure very strong.
Why do ionic compounds have high melting and boiling points?
The electrostatic forces between ions in a crystal lattice are so strong that ionic compounds have very high melting and boiling points.
Why can ionic compounds conduct electricity when molten or when dissolved in water?
When melted or dissolved in water ionic compounds can conduct electricity because the ions are free to move and carry current.
Why are ionic compounds unable to conduct electricity when solid?
When solid ionic compounds are unable to conduct electricity because the ions are not free to move.