Bonding Flashcards
What does mono atomic mean?
Elements exist as single atoms
Group 8
Do not bond with other atoms
Insoluble in water
Do not form ions or conduct electricity
Weak forces between atoms so low melting and boiling points
Bigger atoms have stronger forces between atoms and so a higher melting point
What is simple molecular ?
Simple molecules made of non metals
Covalent bonds between atoms in molecule
Low melting point as weak forces between molecules
Do not conduct electricity as there are no mobile ions
Melting point increases as the size of the molecule increases as the size of intermolecular forces increases
They are isnoluble
What is giant covalent?
Covalent bonding
Insoluble
High melting and boiling points as strong covalent bonds need to be broken
Melting point increases when the strength of covalent bonds increase
What are some examples of giant covalent molecules?
Diamond, silicon ,silicon dioxide which do not conduct electricity
Graphite and graphene which do conduct electricity
What do you know about ionic bonding?
Very high melting point
Do not conduct electricity when solid
Conduct electricity when a liquid so molten or dissolved
Soluble
Why do ionic compounds have very high melting points?
Strong electrostatic forces of attraction between oppositely charged ions
Smaller ions and higher charges increase the strength of the ionic bond which increases the melting point
Why do ionic compounds not conduct when solid?
As the ions are fixed
Why do ionic compounds conduct electricity when molten or dissolved?
As the ions are feee to move
What is metallic bonding?
Bonding between metals
High melting point
They conduct electricity
Metals are insoluble
Why do metallic compounds conduct electricity?
Delocalised electrons carry a charge through the structure
Why do metallic compounds have high melting points?
The attraction between positively charged ions and the delocalised negatively charged electrons
State what you know about ionic bonding
Atoms make bonds between each other by using their outer electrons
They want to gain a more stable electron configuration which is achieved by gaining a full outer shell of electrons
Describe the structure of sodium chloride.
Giant ionic lattice
Strong electrostatic forces of attraction between positive sodium ions Na+ and negative chloride ions Cl-
Must name the ions and not just say oppositely charged ions
Why are ionic compounds solid at room temperature?
Strong electrostatic forces of attraction between positive ions and negative ions
Why do ionic compounds not conduct electricity when solid but do when molten or dissolved?
In a solid ions cannot freely move around and they are fixed
When aqueous ions are feee to move and carry a charge
DO NOT TALK ABOUT ELECTRONS HERE
Why are ionic compounds brittle?
Like charges repel and so the structure shatters
External force may move ions in the lattice and like ions may touch and then repel
When are ionic bonds strongest?
When the size of the ion is smallest and the charge on the ion is high
State what you know about covalent bonding
A shared pair of electrons
Electrons are joined together by electron clouds
Double bonds can form but triple bonds are rare
What is a co ordinate bond?
A covalent bond where both of the electrons in the bond come from just one of the atoms involved
It’s also called a dative covalent bond
What is special about a co ordinate bond?
The atoms that accept electrons are electron deficient and so don’t have a full outer shell
The donating atom donates a lone pair of electrons which is a non bonding pair of electrons
The strength of a co ordinate bond I the same as a regular covalent bond
State what you know about metallic bonding.
Metals can easily lose up to 3 outer electrons
The metal ions are compactly arranged in a lattice- Giant metallic structure
Lots of atoms are joined together
Electrons become part of a delocalised sea of electrons
As you go across the group ionic size decreases and ionic charge increases
What are properties of metallic compounds?
Malleable and ductile
Very strong
High melting points due to strong attractions
What are atoms held together by?
Held together between positive and negative charges of ions
Ionic bonding
What is electronegativity?
The power of an atom to attract the electron density of a covalent bond towards itself