Atoms and Ionic Bonding Flashcards
What are compounds?
Atoms of two or more elements chemically combined together.
What is an isotope?
A different atomic form of the same element with the same number of protons but a different number of neutrons.
What are two isotopes of carbon?
Carbon-12 and carbon-14.
What is ionic bonding?
Atoms gain or lose electrons to form charged particles (ions) which are strongly attracted to each other.
Why are ions strongly attracted to each other?
Opposite charges.
What kind of ions do metals usually form?
Positively charged ions.
What structure do ionic compounds usually form?
Giant ionic lattices.
How are giant ionic lattices held together?
Very strong electrostatic forces of attraction between oppositely charged ions, in all directions.
Why do ionic compounds have high melting and boiling points?
It takes a lot of energy to overcome the strong attraction between the ions.
Under what conditions do ionic compounds conduct electricity?
Molten or dissolved in water.
Why do ionic compounds only conduct electricity when molten or dissolved in water?
The ions can move separately, so they can carry a current.
What is a covalent bond?
Shared pair of electrons.
What are the two structures that can be formed from covalent bonds?
Simple molecules and giant covalent.
Why are melting and boiling points of simple molecules low?
The intermolecular forces are weak.
Why don’t molecular substances conduct electricity?
There are no ions, so there is no electric charge.
What are giant covalent structures also known as?
Macromolecules.
Why do giant covalent structures have high melting and boiling points?
Strong covalent bonds between all the atoms.
Give three examples of giant covalent structures.
- Diamond
- Graphite
- Sand
Why are diamonds hard?
Each carbon atom forms four covalent bonds in a very rigid structure.
Why is graphite soft?
Each carbon atom only forms three covalent bonds, so the layers are able to slide over each other.
Why can graphite be used in pencils?
The intermolecular forces between layers are weak.
Why is graphite a good conductor of heat and electricity?
Each carbon atom has a free electron that conducts heat and electricity.
What is the scientific name for sand?
Silicon dioxide or silica.
What kind of structure do metals form?
Metallic structures.
