bonding

Question 1

Ionic bonding

Answer 1

Strong electrostatic forces of attraction between positive ions and negative ions
Ions are formed when one or more electrons are transferred from oNe atom to another

Question 2

Why group four doesn’t forma charged ion

Answer 2

Form covalent bonds so no charge

Question 3

Compound ions to remember

Answer 3

So4 2- SULFATE
OH- HYDROXIDE
NO3 -
NH4+
CO3 2-

Question 4

Structure of ionic compounds

Answer 4

Each ion attracts oppositely charged ions in all directions
Giant ionic lattice

Question 5

First electron needs the least energy

Answer 5

Being removed from a neutral stom

Question 6

Second electron needs more energy

Answer 6

Because removed from +1ion

Question 7

2nd ionisation equation

Answer 7

X=x2+ +2e-

Question 8

covalent bonding

Answer 8

when non metals shared pair of electrons to get a full outer shell
the overlap of atomic orbitals each containing one electron to give a shared pair of electron
the shared pair of electrons are attracted to the nucleus of both the bonding atoms

Question 9

graphite

Answer 9

each. carbon covalently binder to 3 other carbons
1 delocalised electron conducts electrons
high m+b
weak intermolecular forces

Question 10

electronegativity

Answer 10

the power of an atom to attract the electron density of a covalent bind towards itself
some atoms attract bonding electrons more than others
shorter the distance the more electronegative
greater nucleus charge greater attraction

Question 11

what does electronegativity depend one

Answer 11

1)the nuelcuer charge of the atom
2)the distance between the nucleus and the outer electrons
3)the shielding of nucleus charge by electrons in inner shells

Question 12

across period electronegativity

Answer 12

increases
greater nucleus charge

Question 13

down the group electronegativity

Answer 13

decreases
distance between nucleus and electrons increases

Question 14

electronegatvitiy on the Pauli scale

Answer 14

measured on Pauli scale
4 is largest electronegatvity
nobles gases do not have a value as its unusual for them to form covalent bonds

Question 15

most electronegative element

Answer 15

fluorine

Question 16

polarity

Answer 16

the unequal sharing of electros I bind if the electron sharing is equal the bond is described as non polar

Question 17

intermolecular forces

Answer 17

physical
strong
van der Waals forces
dipole dipole interaction
hydrogen bonds

Question 18

intramoleculer forces

Answer 18

stronger than inter molecular forces
within a molecule
covalent bonds
eg.hydrogen bond is about 1/10TH of a covalent bond

Question 19

strongest to weakens bonding

Answer 19

-metallic
-ionic
-covalent
-hydogen
-permanant dipole-dipole
-instantaneous dipole-dipole

Question 20

permanent dipoles

Answer 20

weak electrostatic forces of attractions with neighbouring molecules

Question 21

similar electromneagtivity

Answer 21

chlorine
hydrohen

Question 22

permanent dipole-dipole forces

Answer 22

molecules with permanent dipole -dipole forces
opposite electronegativites
hydrogen chlorides

Question 23

induced dipole-dipole interactions

Answer 23

-aka London forces /vanderwaals
-doesn’t need to have electronegative difference
1)electrons move this produces changing dipole in molecule
2)instantaneous dipole will exist but its position will constantly change
3)instantaneous dipole induces a dipole in a neighbouring molecule
4)induced dipole induces other dipoles in neighbouring molecules
5)electrons continually move so are created and destroyed all the time overall atoms are attracted to one another
between all molecules at all time
they are in addition to other intermolecular forces
the more electrons in each molecule the larger the induced dipole

Question 24

boiling pint f noble gases increases as atomic number increases

Answer 24

the more electrons
more dipole induced
greater the billing point

Question 25

boiling points of hydrocarbons increase as the chain length increases why

Answer 25

longer carbon chains form more Van der Waals interactions and have greater melting and boiling points

Question 26

explain why the boiling point is higher in hcl and f2

Answer 26

hcl has a permanent dipole whereas fluorine doesn’t therefore more energy is needed to ver come the permanent dipole so it must have a high bp
fluorine as lower bp as it has a instantaneous dipole - dipole interaction therefore its able to form as quickly as it can break so its easy to overcome as its weak and doesn’t last long.

Question 27

explain how induced dipole forms

Answer 27

fluctuation in electron density around molecule
creates instantaneous in molecule
instantaneous dipole induces a dipole in neighbouring molecules

Question 28

hydrogen bonds

Answer 28

special type of permanent dipole-dipole interaction

found between molecules that contain an electronegative atom (O,N,F) and a hydrogen atom
the hydrogen bonds acts between a lone pair of electrons on the electronegative atom and a hydrogen on a different molecule

Question 29

hydrogen bonding higher m+b

Answer 29

stronger in larger numbers as its between many molecules so more energy is needed to overcome
instantaneous- induced dipole /permanant dipole ,hyrdogen bonds

Question 30

why is solid ice less dense than water

Answer 30

solid ice has intermolecular forces holding the molecules vibratining in fixed position and there’s less space between the molecules and therefore its less dense.
the position of hydrogen bonds causes molecules to push farther apart, which lowers the density.
The extra hydrogen bonds that occur when water freezes increase the space between molecules, causing a decrease in overall density. In fact, each water ice molecule forms hydrogen bonds with four other molecules, while water molecules only form hydrogen bonds with an average of 3.4 other molecules.

Question 31

why does water have a relatively high melting and boiling point

Answer 31

water has a high boiling point because its molecules are bound together by hydrogen bonding, which is a very strong intermolecular force. It takes more kinetic energy, or a higher temperature, to break the hydrogen bonding between water molecules, thus allowing them to escape as steam.

Question 32

describe the hydrogen bonding that happens in dna

Answer 32

Hydrogen bonds occur between the two strands and involve a base from one strand with a base from the second in complementary pairing. These hydrogen bonds are individually weak but collectively quite strong.

Question 33

What is needed for hydrogen bonds

Answer 33

LOne pair

Question 34

What forms hydrogen bonds

Answer 34

Oxygen
Nitrogen
Hydrogen

Question 35

Electron pair repulsion theory

Answer 35

-each pair of electrons around an atom will repel all other electron pairs
-the pairs of electrons will therefore take up positions as far apart as possible to minimise repulsion

Question 36

Linear molecule

Answer 36

2e pairs around central atom
Electrons go as far away as possible
180 degrees

Question 37

Trigonal planar

Answer 37

3 electron pairs around central molecule
Electrons go far away as possible
120 degrees

Question 38

Tetrahedral shape

Answer 38

4 bonding pairs of electrons as far apart as possible
109.5

Question 39

Solid lime

Answer 39

Represents a bind in the plane of the paper

Question 40

Wedge

Answer 40

Comes out of the plane Kf the pape

Question 41

Dotted wedge

Answer 41

Into the plane of the paper

Question 42

Trigonal bioyramidq

Answer 42

5 electron pairs

Question 43

Octahedral

Answer 43

6 electrons
90 degrees

Question 44

valence shell electron pair repulsion

Answer 44

a lone pair of electrons is slightly closer to the central atom

it occupies more space than a bonding pair

lone pairs repel more strongly so change the shape

keep your methane , then build NH3

Question 45

polarity

Answer 45

the unequal sharing of electros I bind if the electron sharing is equal the bond is described as non polar