1.4 Bonding

Question 1

What is ionic bonding?

Answer 1

bonding between metals and non-metals
one atom donates one or more electrons to another, resulting in the formation of a cation and an anion

Question 2

What is covalent bonding?

Answer 2

between non-metal atoms
where each atom gives one electron to the shared pair of electrons
there is a strong electrostatic attraction between the shared pair of electrons and the nuclei of both atoms. This outweighs the repulsion between the electrons in the shared pair. Also, both electrons in the bond have opposing spins to minimise this repulsion

Question 3

Are covalent bonds strong?

Answer 3

covalent bonds are very strong and require a high temperature to break them

Question 4

What is a coordinate bond?

Answer 4

covalent bond where both electrons in the bond come from the same atom

Question 5

What is polarity in bonds?

Answer 5

in a molecule with the same atoms, the shared electrons in the single covalent bond are shared evenly between the atoms, whereas if a molecule where the atoms are not the same, then the electron pair is not shared evenly between the two atoms, leading one atom in the molecule to be slightly more negative than the other

Question 6

What covalent bonds aren’t polar?

Answer 6

if the atoms are the same
have the same effect on the shared electrons

Question 7

Are coordinate bonds polar?

Answer 7

yes because it is one of the atoms that donates both electrons and is the one that has most right over the electrons

Question 8

What is polarity determined by?

Answer 8

electronegativity

Question 9

What is the relationship between polarity and electronegativity?

Answer 9

the larger the difference in electronegativity the more polar it is

Question 10

What is an intramolecular force?

Answer 10

forces within molecules

Question 11

What is an intermolecular force?

Answer 11

forces between molecules

Question 12

What is an induced dipole dipole interaction/ temporary dipoles?

Answer 12

weakest type of intermolecular bond
when a temporary dipole is formed instantaneously due to random electron movement, it causes an induced dipole in a neighbouring molecule, as a result van Der waal’s forces exist between the molecules

Question 13

State how a coordinate bond differs from a covalent bond

Answer 13

in a coordinate bond both bonding electrons come from one atom while in a covalent bond both atoms contribute one electron in the shared pair

Question 14

give examples of species containing a coordinate bond

Answer 14

Al2Cl6
NH4+

Question 15

How are ions arranged in an ionic bond?

Answer 15

the cations and anions in an ionic bond are arranged so that each anion is surrounded by a certain number of cations and vice versa so that there is maximum attraction obtained and also minimum repulsion

Question 16

What is electronegativity?

Answer 16

the ability of an atom to attract a pair of electrons within a covalent bond

Question 17

What are the 3 most electronegative elements?

Answer 17

Nitrogen
Oxygen
Fluorine

Question 18

When are hydrogen bonds formed?

Answer 18

only when hydrogen is directly bonded to nitrogen, oxygen or fluorine

Question 19

What are more stronger vdw or hydrogen bonds?

Answer 19

hydrogen bonds

Question 20

What are dipole dipole forces/ permanent dipoles?

Answer 20

Polar molecules have dipoles. One end has a slightly positive charge, the other a slightly negative charge due to a difference in electronegativities between the atoms in the molecule. If these dipoles arrange themselves so that the negative region of one molecule is close to the positive region of another molecule, there will be an attraction between them.

Question 21

What is a lone pair of electrons?

Answer 21

a pair of electrons in the valence shell, not involved in bonding

Question 22

Why do simple molecular structures have a low melting and boiling point?

Answer 22

because they have weak intermolecular forces between the molecules, which only require a small amount energy to break the forces

Question 23

What are the effects of dipoles on melting and boiling points?

Answer 23

the larger the dipole the higher the m.p/b.p of a substance
the larger the molecule the more vdw forces can exist and the higher the m.p/b.p
If hydrogen is directly bonded to N,O,F, then hydrogen bonding can exist between molecules and the m.p/b.p will be higher than expected