Covalent bonding Flashcards
What is a covalent bond?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms.
who does it occur between?
between 2 non metals
What is used to represent covalent bonds?
Dot-cross diagrams
What happens in a covalent bond?
electrons are SHARED between the atoms and atoms obtain a FULL OUTER SHELL of electrons
Which type of bond includes sharing only one pair of electrons
Single covalent bond
what type of covalent bonding is H20
single covalent
What is the type of bonding when more than 1 pair of electrons is shared
multiple covalent bonding
Which type of bond includes sharing only TWO PAIRS of electrons
double bond
Which type of bond includes sharing only 3 pairs of electrons
triple bond
What is dative covalent bonding
One atom donates both of the electrons in a covalent bond (i.e donates a lone pair)
example of a molecule where there is dative covalent bonding?
NH4+ (AMMONIUM)
why is the ammonium positive overall?
The hydrogen lost an electron an d received a lone pair from nitrogen in a dative covalent bond
What is another name for dative covalent bonds
co-ordinate bonds
example of a molecule where there is triple covalent bonding
N2 (Nitrogen gas)
What are substances made of simple molecules
simple molecular substances
what forces are between each MOLECULE in the simple substance
weak intermolecular forces
Do simple molecular substances have low or high melting and boiling point?
low due to weak intermolecular forces
why do simple molecular substances have low b.p and m.p?
WEAK intermolecular forces
between THE MOLECULES
so LOW AMOUNT OF ENERGY needed to DISRUPT these intermolecular forces
simple molecular substances are SOLUBLE in non polar solvents true or false
TRUE
can simple molecular substances conduct electricity ?
Why?
No, since there are no electrons or particles that can move freely and carry charge
Example of giant covalent substance
SiO2 (silicon dioxide)
giant covalent substances have high melting and boiling point. (TRUE OR FALSE)
True
why do giant covalent substances have high melting and boiling point?
-Strong covalent bond existing throughout the lattice
-Lots of energy is required to break these bonds between atoms therefore high melting and boiling point
Are giant covalent substances soluble in polar or non-polar solvents?
No, they are insoluble in either of the two.
WHY Are giant covalent substances insoluble in polar and non-polar solvents?
Strong covalent bonds are not disrupted by any of the solvents
can giant covalent substances conduct electricity? is there an exception?
No, they cannot due to absence of freely moving particles which can carry charge. But graphite is an exception and has delocalised electrons between the layers of lattice
What happens when electrons are applied to graphite
electrons move freely parallel to graphite layers and conduct electricity
Do covalent compounds have molecular LATTICE or exist as molecules in SOLID STATE?
LATTICE STRUCTURE
