3 - Bonding Flashcards
What are ionic bonds?
Bonds formed between elements whose atoms need to lose and gain electrons to become isoelectronic with the nearest noble gas configuration, electrons are transferred from one atom to the other.
What are the four chemical bonds?
Ionic
Covalent
Dative
Metallic
What is the simple definition of ionic bonding?
Oppositely charged ions held together in a crystal lattice by electrostatic attraction.
What are positive ions and their properties?
Cations
Formed when electrons removed
Smaller than original atom
Endothermic process
What are negative ions and their properties?
Anions.
Formed when electrons are added to the atom.
Larger than original atom due electron repulsion.
Exothermic process.
What is a giant ionic crystal lattice?
Oppositely charged ions held together in a 3D lattice by electrostatic attraction.
What is the definition of covalent bonding?
Consists of a shared pair of electrons with one electron being supplied by each atom either side of the bond.
Atoms are held together as their positively charged nuclei are attracted to the shared electrons.
What do covalent bonds form between?
Atoms of the same or different elements
Elements in group 4
Head of the group elements
High ionisation energies
What is the orbital theory with covalent bonds?
Covalent bonds are formed when orbitals with one electron each overlap, this forms a region in space where an electron pair can be found.
Greater overlap = stronger bond
What is sigma bond?
A type of covalent bond formed by two orbitals overlaping along the axis connecting the two nuclei.
Forming an area of high electron density between the nuclei.
What is pi bond?
A type of covalent bond formed from the sidways overlap of orbitals. Creating an area of high electron density above and below the nuclei.
Explain electron exceptions with covalent bonding?
Some don’t achieve an octet
Some will exceed their octet, atoms from period 3 can due to empty d orbitals.
What is dative covalent bonding?
Where both electrons in the shared pair of electrons are provided by one species.
Donor species will have lone pairs of electrons and acceptor species will not achieve an octet.
What is a hazard?
Something that may cause harm.
What is a risk?
The likelihood that someone will be harmed by the hazard.
What is electronegativity?
The power of an atom to attract the shared pair of electrons in a covalent bond.
What is the most electronegative atom?
Fluorine
What 3 factors affect electronegativity?
Nuclear charge
Atomic radius
Shielding
How does nuclear charge affect electronegativity?
An increase in protons means a stronger attraction from the nucleus to the bonding pair of electrons, increasing electronegativity.
How does atomic radius affect electronegativity?
The smaller the atomic radius the closer the bonding electrons to the nucleus, the greater the attraction, therefore the greater the electronegativity.
How does shielding affect electronegativity?
The fewer the shells, the less the shielding of the bonding electrons, therefore the stronger the attraction from the nucleus, increasing the electronegativity.