Topic 2 Using Spec Flashcards
(52 cards)
What happens when an atom loses one or more electrons
It becomes a cation - a positively charged ion
What happens when an atom gains one or more electrons
Becomes an anion - a negatively charged ion
How are ionic bonds formed
When the transfer of electrons occurs an electrostatic attraction between the two ions of opposite charge takes place and an ionic bond is formed.
What is an ion
An ion is an atom or group of atoms with a positive or negative charge .
When do materials with ionic bonds conduct electricity
When molten and high melting points
When do ionic compounds end in -ide
When made from 2 different elements
When do ionic compounds end in -ate
When the ionic compound is made from 3 or more different elements
Explain the structure of an ionic compound as a lattice structure
Oppositely charged ions are held together in ionic lattices. Ionic lattices are giant structures that are held together by strong electrostatic forces between the positive and negative ions.
Deduce the formula for sodium carbonate.
Sodium carbonate contains Na+ and CO32- ions:
this is one positive charge and two negative charges
to balance, two Na+ ions and one CO32- ions are needed
so the formula is Na2CO3
Explain how a covalent bond is formed when a pair of electrons is shared between two atoms
Covalent bonds are formed when 2 non-metal atoms share pairs of electrons.
These electrons are found on the outer shell of the atoms. Covalent bonds are strong because the shared electrons are attracted to the nucleus of both atoms
covalent bonding results in the formation of what molecules?
Small molecules (water) Large molecules (polymers) Giant covalent structures (diamond)
What kind of covalent bond is hydrogen
Single covalent bond as each hydrogen atom shares 1 electron with the other
What kind of covalent bond is water
Single covalent with 2 hydrogen atoms
What type of covalent bond is oxygen
Double covalent bond as it needs 2 electrons to get a full outer shell
What are the properties of the lattice structure in the ionic compounds
High melting and boiling points
Don’t conduct electricity if solid
Conduct electricity if liquid or in solution
Why do lattice structures have a high melting and boiling point
Because to break the ionic bonds, a lot of energy is needed to overcome the electrostatic forces between the ions and electrons.
Why can’t the lattice structure conduct electricity if solid
When solid the ions are fixed in place therefore charges cannot flow so electricity cannot be conducted
Why can the lattice structure conduct electricity if liquid or in solution
When molten or dissolved in water, the ions in the lattice can move freely therefore charges can flow and electricity can be conducted
What is an example of a small molecule
Chlorine as it has weak intermolecular forces between its molecules
What is an example of a bigger molecule
Sucrose as its intermolecular forced are strong
What are the properties of small covalent molecules
Lower melting/boiling points
Don’t conduct electricity
What are the properties of large covalent molecules
High melting/boiling point
Don’t conduct electricity
Why are small covalent molecules liquid or gases at room temperature
When small molecules melt or boil, it’s the weak intermolecular forces that break.
Since these intermolecular forces are weak and break easily, simple covalent molecules have very low melting and boiling points.
Therefore, they exist as liquid and gases at room temperature.
What are the properties of giant covalent structures
Very high melting points
1 large molecule
