Bonding Flashcards
How many MAIN types of bonding are seen in elements and compounds
3
What are the elements like in COVALENT bonds
non-metals
What are the elements like in IONIC bonds
metals + non-metals
What are the elements like in METALLIC bonds
metals
what is a covalent bond
an attraction between 2 atoms where a shared pair of electrons form a bond
What holds the negatively charged electrons in a covalent bond
the positive nuclei
What is a molecule
a substance when 2 or more atoms are held together by covalent bond
How many elements exist as molecules (they are also known as the diatomic elements)
7
How many shared pairs of electrons form a SINGLE covalent bond
1
How many shared pairs of electrons form a DOUBLE covalent bond
2
How many shared pairs of electrons form a TRIPLE covalent bond
3
What are covalent network structures
compounds made up of non metal atoms which are joined together by covalent bonds in a giant network structure
Give 3 examples of Covalent network structures
Carbon- Diamond and graphite
Silicon Dioxide (sand)
Can covalent network structures dissolve in water?
no but they can dissolve in other covalent liquids
Do ions have a charge
yes
Do metal atoms gain or lose electrons
Metal atoms always LOSE electrons to form POSITIVE metal ions
Do non-metal atoms gain or lose electrons
Non-metal atoms always GAIN electrons to form NEGATIVE metal ions
How are ionic compounds normally formed
when metal and non-metal elements combine
What is ionic bonding, by defenition
the electrostatic attraction between ions of opposite charge
What do ionic compounds exist as?
a giant lattice structure of oppositely charged ions
How do metallic structures exist as?
a giant metallic lattice of positively charged ions and delocalised outer electrons
What is electricity
the flow of charged particles ( electrons or ions)
What needs to happen to substances for them to conduct
must have charged particles which are free to move and carry the electricity
When do metals conduct electricity
when in liquid or solid
When do non metals conduct electricity
they don’t ( except graphite)
When do ionic compounds conduct electricity
in aqueous form but not when in solid form
Why do ionic substances only conduct in solution
the charged particles are free to move and carry the electricity
Are ionic compounds solid at room tmperature
yes
What state are covalent compounds at room temperature
solids, liquids or gasses
How strong are metallic bonds
very
What happens when a solid metal melts
the atoms move and become more disarranged
How can atoms move in the strong metallic bonds
Break the bonds
What are ions in a crystal lattice held together with
strong forces of attraction
When an ionic solid melts the ions move apart. The amount of energy needed to separate the ions is ____
High
Can covalent bonds break
not easily although their inter molecular forces are weak and easily broken
What are the 2 types of compounds
Molecular (covalent) and ionic
Why can covalent molecular and network substances not conduct electricity
they do not have charged particles that are free to move and carry electricity
What happens when ionic compounds dissolve in water
the ions separate and are surrounded by water molecules
Name the 7 diatomic elements
Hydrogen
Nitrogen
Oxygen
Fluorine
Chlorine
Bromine
Iodine
Why are covalent bonds strong
the force of attraction between the positive nuclei and the negative electrons in the overlap region is strong
Do ionic compounds have high or low melting points
high since at melting point, strong ionic bonds within the lattice need to be broken in order to overcome the lattice
Do covalent substances have high or low melting points
low because the attractions between molecules (inter molecular forces)are easy to overcome when the substance changes state
Do covalent network compounds have high or low melting points
Millions of strong covalent bonds need to be broken for a change of state so high
Do covalent molecular compounds have high or low melting points
low since at melting point, no covalent bonds are broken since they are strong. although heir inter molecular forces are weak and easily broken
What does the term diatomic molecule mean
Diatomic- 2 atoms joined together
molecule- atoms joined together by a covalent bond
name the 2 types of covalent structures
network
molecular
describe the bonds in covalent substances
Bonds inside the molecules are strong
Bonds between molecules are weak forces of attraction
Explain why discrete covalent substances have low melting and boiling points
Weak bonds in between molecules are broken where there is a change of state, no strong covalent bonds
Describe the structure of covalent network substances
Complex structure of millions of strong covalent bonds
Why can graphite conduct electricity
it has free moving electrons
What does the ending -ide tell u about a compound and give an exception
Contains 2 elements only except hydroxide which is a group ion
What does the name ending -ite or -ate tell u about a compound
2 elements present and oxygen
Some covalent substances are made up of ____________________ . These different molecules are held together by weak forces known as ______________________
discrete molecules
inter-molecular forces
What is the definition for the word DIATOMIC
exist as 2 atoms covalent bonded
